minocycline and Spinal-Cord-Injuries

Spinal cord injury (SCI) is one of the most debilitating of all the traumatic conditions that afflict individuals. For a number of years, extensive studies have been conducted to clarify the molecular mechanisms of SCI. Experimental and clinical studies have indicated that two phases, primary damage and secondary damage, are involved in SCI. The initial mechanical damage is caused by local impairment of the spinal cord. In addition, the fundamental mechanisms are associated with hyperflexion, hyperextension, axial loading and rotation. By contrast, secondary injury mechanisms are led by systemic and cellular factors, which may also be initiated by the primary injury. Although significant advances in supportive care have improved clinical outcomes in recent years, a number of studies continue to explore specific pharmacological therapies to minimize SCI. The present review summarized some important pathophysiologic mechanisms that are involved in SCI and focused on several pharmacological and non‑pharmacological therapies, which have either been previously investigated or have a potential in the management of this debilitating injury in the near future.

Topics: Animals; Cyclooxygenase Inhibitors; Humans; Minocycline; Neuroprotective Agents; Spinal Cord; Spinal Cord Injuries

Topics: ADP Ribose Transferases; Botulinum Toxins; Cell Transplantation; Decompression, Surgical; Hemodynamics; Humans; Hypothermia, Induced; Methylprednisolone Hemisuccinate; Minocycline; Neuroprotective Agents; Riluzole; Spinal Cord Injuries; Treatment Outcome

There is a need to enhance the pipeline of discovery and evaluation of neuroprotective pharmacological agents for patients with spinal cord injury (SCI). Although much effort and money has been expended on discovering effective agents for acute and subacute SCI, no agents that produce major benefit have been proven to date. The deficiencies of all aspects of the pipeline, including the basic science input and the clinical testing output, require examination to determine remedial strategies. Where has the neuroprotective/pharmacotherapy preclinical process failed and what needs to be done to achieve success? These are the questions raised in the present review, which has 2 objectives: 1) identification of articles that address issues related to the translational readiness of preclinical SCI pharmacological therapies; and 2) examination of the preclinical studies of 5 selected agents evaluated in animal models of SCI (including blunt force trauma, penetrating trauma, or ischemia). The 5 agents were riluzole, glyburide, magnesium sulfate, nimodipine, and minocycline, and these were selected because of their promise of translational readiness as determined by the North American Clinical Trials Network Consortium. The authors found that there are major deficiencies in the effort that has been extended to coordinate and conduct preclinical neuroprotection/pharmacotherapy trials in the SCI field. Apart from a few notable exceptions such as the NIH effort to replicate promising strategies, this field has been poorly coordinated. Only a small number of articles have even attempted an overall evaluation of the neuroprotective/pharmacotherapy agents used in preclinical SCI trials. There is no consensus about how to select the agents for translation to humans on the basis of their preclinical performance and according to agreed-upon preclinical performance criteria. In the absence of such a system and to select the next agent for translation, the Consortium has developed a Treatment Strategy Selection Committee, and this committee selected the most promising 5 agents for potential translation. The results show that the preclinical work on these 5 agents has left numerous gaps in knowledge about their preclinical performance and confirm the need for significant changes in preclinical neuroprotection/pharmacotherapy trials in SCI. A recommendation is made for the development and validation of a preclinical scoring system involving worldwide experts in preclinical a

Topics: Animals; Disease Models, Animal; Glyburide; Humans; Magnesium Sulfate; Minocycline; Neuroprotective Agents; Nimodipine; Riluzole; Spinal Cord Injuries; Translational Research, Biomedical

Spinal cord injury leads to a devastating cascade of secondary complications that eventually results in the formation of scar tissue many times the size of the original insult. Inflammation plays a very important role towards the development of such scar, but paradoxically, at the same time it has neuroprotective properties. Only recently have we understood enough about the relevant events to make the repair of injured spinal cords a reachable goal. Over the past decade, researchers have designed and tested numerous innovative therapeutic strategies, and many of such involve manipulation of the immune response. Interestingly, both immuno-stimulatory and immuno-suppressive interventions have shown positive results, which include the prevention of further tissue damage, prevention of secondary cell death and axonal degeneration, promotion of remyelination, stimulation of axonal regeneration, and facilitation of sensorimotor function recovery.

Topics: Erythropoietin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Inflammation; Lymphocyte Activation; Macrophage Activation; Minocycline; Neutrophils; Peptides; rho-Associated Kinases; Spinal Cord Injuries; T-Lymphocytes

The secondary cascade of cell death that follows central nervous system (CNS) injury or ischemia has long been considered a target for neuroprotective agents aimed at sparing tissue and function. Recently, several laboratories have shown remarkable protection and recovery of function in rodent models of spinal cord injury using treatments that target components of the CNS inflammatory response. The use of minocycline, an antibiotic that reduces microglial activation, antibody blockade of the CD95 (FAS) ligand and the blockade of glycosphingolipid-induced iNOS (inducible nitric oxide synthase) have recently been shown to reduce neuronal and glial apoptosis with concomitant improvement in neurological function, and appear to enhance the efficacy of cell transplantation strategies.

Topics: Animals; Antibodies; Apoptosis; fas Receptor; Inflammation; Microglia; Minocycline; Nitric Acid; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Rats; Spinal Cord Injuries; Tumor Necrosis Factor-alpha

Inflammatory changes after spinal cord injury (SCI) have been reported in animal models, but human studies are relatively limited. We examined cerebrospinal fluid (CSF) collected from subjects enrolled in a phase II placebo-controlled trial of minocycline for evidence of inflammatory and structural changes after acute human SCI. CSF was collected from 29 subjects every 6 h for 7 days and investigated for eight molecules. CSF from 6 normal subjects (lumbar microdiscectomy patients without central nervous system pathology) was also examined for comparison. Cumulative levels of CSF molecules were compared between patients with motor complete and motor incomplete injury, between those receiving minocycline or placebo, and correlated to neurological outcome at 1 year (alpha = 0.05). We found that levels of C-C motif chemokine ligand 2 (monocyte chemoattractant), C-X-C motif chemokine 10 (CXCL10; T-cell chemoattractant), interleukin-1β (IL-1β), matrix metalloproteinase-9 (MMP-9), neurofilament heavy chain (NfH), and heme oxygenase-1 (HO-1) were significantly elevated after SCI. Neural cell adhesion molecule and nitric oxide oxidation products (NOx) were not significantly altered. Levels of IL-1β, MMP-9, and HO-1 were higher in subjects with more severe motor impairment. Higher cumulative levels of IL-1β, MMP-9, and CXCL10 exhibited moderate, but significant, correlation with worse motor recovery at 12 months. Only HO-1 and NfH appeared to vary with minocycline treatment; HO-1 lacked a later peak compared to placebo-treated subjects while NfH did not manifest its early peak with treatment. These analyses of CSF biomarkers imply a pathophysiological role for particular molecules and suggest mechanistic targets for minocycline in human traumatic SCI.

Topics: Biomarkers; Cytokines; Humans; Inflammation; Minocycline; Neuroprotective Agents; Recovery of Function; Spinal Cord Injuries

Neurofilaments (Nf) are major structural proteins that occur exclusively in neurons. In spinal cord injury (SCI), the severity of disease is quantified by clinical measures that have limited sensitivity and reliability, and no blood-based biomarker has been established to further stratify the degree of injury. We aimed to examine a serum-based NfL immunoassay as predictor of the clinical outcome in SCI.. Longitudinal measurement of serum NfL was performed in patients with central cord syndrome (CCS, n=4), motor-incomplete SCI (iSCI, n=10), motor-complete SCI (cSCI, n=13) and healthy controls (HC, n=67), and correlated with clinical severity, neurological outcome, and neuroprotective effect of the drug minocycline.. Baseline NfL levels were higher in iSCI (21 pg/mL) and cSCI (70 pg/mL) than in HC (5 pg/mL, p=0.006 and p<0.001) and CCS (6 pg/mL, p=0.025 and p=0.010). Levels increased over time (p<0.001) and remained higher in cSCI versus iSCI (p=0.011) and than in CCS (p<0.001). NfL levels correlated with American Spinal Injury Association (ASIA) motor score at baseline (r=-0.53, p=0.004) and after 24 h (r=-0.69, p<0.001) and 3-12-month motor outcome (baseline NfL: r=-0.43, p=0.026 and 24 h NfL: r=-0.72, p<0.001). Minocycline treatment showed decreased NfL levels in the subgroup of cSCI patients.. Serum NfL concentrations in SCI patients show a close correlation with acute severity and neurological outcome. Our data provide evidence that serum NfL is of prognostic value in SCI patients for the first time. Further, blood NfL levels may qualify as drug response markers in SCI.

Topics: Adult; Anti-Bacterial Agents; Biomarkers; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Infusions, Intravenous; Longitudinal Studies; Male; Middle Aged; Minocycline; Neurofilament Proteins; Neurologic Examination; Prognosis; Reference Values; Spinal Cord Injuries

Preclinical studies have attributed neuroprotective properties to the antibiotic minocycline. Animal studies and early clinical trials support its use in several neurological diseases. In animal spinal cord injury models, minocycline improved neurological and histological outcomes, reduced neuronal and oligodendroglial apoptosis, decreased microglial activation and reduced inflammation. A single-centre, human, double-blind, randomized, placebo-controlled study of minocycline administration after spinal cord injury was undertaken for the purposes of dose optimization, safety assessment and to estimate outcome changes and variance. Neurological, functional, pharmacological and adverse event outcomes were compared between subjects administered 7 days of intravenous minocycline (n = 27) or placebo (n = 25) after acute traumatic spinal cord injury. The secondary outcome used to assess neurological differences between groups that may warrant further investigation was motor recovery over 1 year using the American Spinal Cord Injury Association examination. Recruitment and analyses were stratified by injury severity and injury location a priori given the expected influence of these on the sensitivity of the motor exam. Minocycline administered at higher than previously reported human doses produced steady-state concentrations of 12.7 µg/ml (95% confidence interval 11.6-13.8) in serum and 2.3 µg/ml (95% confidence interval 2.1-2.5) in cerebrospinal fluid, mimicking efficacious serum levels measured in animal studies. Transient elevation of serum liver enzymes in one patient was the only adverse event likely related to the study drug. Overall, patients treated with minocycline experienced six points greater motor recovery than those receiving placebo (95% confidence interval -3 to 14; P = 0.20, n = 44). No difference in recovery was observed for thoracic spinal cord injury (n = 16). A difference of 14 motor points that approached significance was observed in patients with cervical injury (95% confidence interval 0-28; P = 0.05, n = 25). Patients with cervical motor-incomplete injury may have experienced a larger difference (results not statistically significant, n = 9). Functional outcomes exhibited differences that lacked statistical significance but that may be suggestive of improvement in patients receiving the study drug. The minocycline regimen established in this study proved feasible, safe and was associated with a tendency towards improvement across several

Topics: Acute Disease; Adult; Dose-Response Relationship, Drug; Double-Blind Method; Female; Follow-Up Studies; Humans; Male; Minocycline; Neurologic Examination; Recovery of Function; Retrospective Studies; Severity of Illness Index; Spinal Cord Injuries; Time Factors; Young Adult

Opioids are among the most effective analgesics for the management of pain in the acute phase of a spinal cord injury (SCI), and approximately 80% of patients are treated with morphine in the first 24 h following SCI. We have found that morphine treatment in the first 7 days after SCI increases symptoms of pain at 42 days post-injury and undermines the recovery of locomotor function in a rodent model. Prior research has implicated microglia/macrophages in opioid-induced hyperalgesia and the development of neuropathic pain. We hypothesized that glial activation may also underlie the development of morphine-induced pain and cell death after SCI. Supporting this hypothesis, our previous studies found that intrathecal and intravenous morphine increase the number of activated microglia and macrophages present at the spinal lesion site, and that the adverse effects of intrathecal morphine can be blocked with intrathecal minocycline. Recognizing that the cellular expression of opioid receptors, and the intracellular signaling pathways engaged, can change with repeated administration of opioids, the current study tested whether minocycline was also protective with repeated intravenous morphine administration, more closely simulating clinical treatment. Using a rat model of SCI, we co-administered intravenous morphine and intrathecal minocycline for the first 7 days post injury and monitored sensory and locomotor recovery. Contrary to our hypothesis and previous findings with intrathecal morphine, we found that minocycline did not prevent the negative effects of morphine. Surprisingly, we also found that intrathecal minocycline alone is detrimental for locomotor recovery after SCI. Using ex vivo cell cultures, we investigated how minocycline and morphine altered microglia/macrophage function. Commensurate with published studies, we found that minocycline blocked the effects of morphine on the release of pro-inflammatory cytokines but, like morphine, it increased glial phagocytosis. While phagocytosis is critical for the removal of cellular and extracellular debris at the spinal injury site, increased phagocytosis after injury has been linked to the clearance of stressed but viable neurons and protracted inflammation. In sum, our data suggest that both morphine and minocycline alter the acute immune response, and reduce locomotor recovery after SCI.

Topics: Analgesics, Opioid; Animals; Minocycline; Morphine; Neuralgia; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord; Spinal Cord Injuries

Traumatic spinal cord injury (TSCI) induces a powerful inflammatory response that can significantly exacerbate the extent and severity of neural damage (termed as "secondary injury"). Thus, the suppression of inflammation is crucial for reducing neurological dysfunction following TSCI. However, the conventional anti-inflammatory drugs show limited efficacy because of poor penetration and release kinetics at the injury site. This study describes the design, synthesis, release kinetics, biosafety, and preclinical efficacy of minocycline (MC)-loaded poly(α-lipoic acid)-methylprednisolone (PαLA-MP) prodrug nanoparticles (NPs) for the combined anti-inflammatory treatment of TSCI.. NPs were produced by conjugating MP to PαLA and then loading MC. The NP structure was confirmed through. The MC-PαLA-MP NPs exhibited high biocompatibility and released 81% MC and 54% MP within 24 h under TSCI-like conditions, effectively reducing 40% of pro-inflammatory cytokine release both in cultures and injured rat spinal cord tissues. Systemic injection increased the Basso, Beattie, Bresnahan score of TSCI rats from 2.33 ± 0.52 to 8.83 ± 1.83 in 8 weeks, providing effective neuroprotection and enhanced exercise recovery in the TSCI rats.. The MC-PαLA-MP NPs can mitigate secondary inflammation and preserve motor function following experimental TSCI, which suggests their potential for clinical application.

Topics: Animals; Anti-Inflammatory Agents; Methylprednisolone; Minocycline; Nanoparticles; Prodrugs; Rats; Recovery of Function; Spinal Cord; Spinal Cord Injuries; Thioctic Acid

After primary injury to the spinal cord, a series of microenvironmental changes can lead to secondary injury. The use of nano-targeted drug delivery systems to improve the postinjury microenvironment, inhibit inflammation and reduce neuronal apoptosis can be of great help during spinal cord injury (SCI) recovery. In this study, we prepared primary macrophage membranes bionic modified nanoliposomes (MH-DS@M-Lips) loaded with minocycline hydrochloride (MH) and dextran sulfate (DS) to target their delivery to the site of injury to bind calcium ions in situ and form metal ion complexes. Complex formation reduced calcium ion concentrations and calcium-associated neuronal apoptosis, while MH was slowly released to produce better anti-inflammatory effects. The successful preparation of MH-DS@M-Lips was verified using transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), western blotting and dynamic light scattering (DLS). The targeting capability of the MH-DS@M-Lips was demonstrated using a Transwell system and an in vivo imaging system. The therapeutic efficacy of MH-DS@M-Lips was examined in vitro and in vivo using flow cytometry, immunofluorescence, ELISA kits and western blotting. The results showed that SCI mice treated with MH-DS@M-Lips received high behavioral scores, which led to the conclusion that MH-DS@M-Lips have great potential for the treatment of SCI.

Topics: Animals; Bionics; Calcium; Dextran Sulfate; Ions; Liposomes; Mice; Minocycline; Neuroprotective Agents; Spinal Cord; Spinal Cord Injuries

Study explore the effects of minocycline on the expression of glial fibrillary acidic protein and brain-derived neurotrophic factor after spinal cord injury and its possible mechanism of action.. The model of acute spinal cord injury was established by Allen's method. The rats in each group were assessed with Basso Beattie Bresnahan score of hindlimb motor function and inclined plate test score. Serum malondialdehyde and superoxide dismutase, glial fibrillary acidic protein and brain-derived neurotrophic factor in spinal cord were compared.. Basso Beattie Bresnahan scores, Tiltboard experiment max angles, and Serum superoxide dismutase activity of the minocycline group were higher than those of the model group after surgery (P < 0.05). Serum malondialdehyde content, and expression of the minocycline group was lower than that of the model group (P < 0.05), and brain-derived neurotrophic factorexpression of minocycline group was significantly higher in the model group after surgery (P < 0.05). Minocycline can promote the recovery of motor function after spinal cord injury in rats.. The mechanism of action may be that it inhibits local free radical generation, reduces lipid peroxidation and glial fibrillary acidic protein expression in spinal cord tissue after spinal cord injury, and promotes the synthesis of endogenous brain-derived neurotrophic factor, thus improving the microenvironment of spinal cord regeneration after spinal cord injury in rats.

Topics: Animals; Brain-Derived Neurotrophic Factor; Disease Models, Animal; Female; Free Radicals; Glial Fibrillary Acidic Protein; Lipid Peroxidation; Male; Minocycline; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord; Spinal Cord Injuries; Spinal Cord Regeneration

Minocycline is a clinically available synthetic tetracycline derivative with anti-inflammatory and antibiotic properties. The majority of studies show that minocycline can reduce tissue damage and improve functional recovery following central nervous system injuries, mainly attributed to the drug's direct anti-inflammatory, anti-oxidative, and neuroprotective properties. Surprisingly the consequences of minocycline's antibiotic (i.e., antibacterial) effects on the gut microbiota and systemic immune response after spinal cord injury have largely been ignored despite their links to changes in mental health and immune suppression.. Here, we sought to determine minocycline's effect on spinal cord injury-induced changes in the microbiota-immune axis using a cervical contusion injury in female Lewis rats. We investigated a group that received minocycline following spinal cord injury (immediately after injury for 7 days), an untreated spinal cord injury group, an untreated uninjured group, and an uninjured group that received minocycline. Plasma levels of cytokines/chemokines and fecal microbiota composition (using 16s rRNA sequencing) were monitored for 4 weeks following spinal cord injury as measures of the microbiota-immune axis. Additionally, motor recovery and anxiety-like behavior were assessed throughout the study, and microglial activation was analyzed immediately rostral to, caudal to, and at the lesion epicenter.. We found that minocycline had a profound acute effect on the microbiota diversity and composition, which was paralleled by the subsequent normalization of spinal cord injury-induced suppression of cytokines/chemokines. Importantly, gut dysbiosis following spinal cord injury has been linked to the development of anxiety-like behavior, which was also decreased by minocycline. Furthermore, although minocycline attenuated spinal cord injury-induced microglial activation, it did not affect the lesion size or promote measurable motor recovery.. We show that minocycline's microbiota effects precede its long-term effects on systemic cytokines and chemokines following spinal cord injury. These results provide an exciting new target of minocycline as a therapeutic for central nervous system diseases and injuries.

Topics: Animals; Anxiety; Cytokines; Disease Models, Animal; Dysbiosis; Female; Gastrointestinal Microbiome; Inflammation; Microglia; Minocycline; Rats; Rats, Inbred Lew; Recovery of Function; Spinal Cord Injuries

Spinal cord injury (SCI) induces pathological and inflammatory responses that create an inhibitory environment at the site of trauma, resulting in axonal degeneration and functional disability. Combination therapies targeting multiple aspects of the injury, will likely be more effective than single therapies to facilitate tissue regeneration after SCI. In this study, we designed a dual-delivery system consisting of a neuroprotective drug, minocycline hydrochloride (MH), and a neuroregenerative drug, paclitaxel (PTX), to enhance tissue regeneration in a rat hemisection model of SCI. For this purpose, PTX-encapsulated poly (lactic-co-glycolic acid) PLGA microspheres along with MH were incorporated into the alginate hydrogel. A prolonged and sustained release of MH and PTX from the alginate hydrogel was obtained over eight weeks. The obtained hydrogels loaded with a combination of both drugs or each of them alone, along with the blank hydrogel (devoid of any drugs) were injected into the lesion site after SCI (at the acute phase). Histological assessments showed that the dual-drug treatment reduced inflammation after seven days. Moreover, a decrease in the scar tissue, as well as an increase in neuronal regeneration was observed after 28 days in rats treated with dual-drug delivery system. Over time, a fast and sustained functional improvement was achieved in animals that received dual-drug treatment compared with other experimental groups. This study provides a novel dual-drug delivery system that can be developed to test for a variety of SCI models or neurological disorders.

Topics: Animals; Hydrogels; Minocycline; Nerve Regeneration; Paclitaxel; Rats; Spinal Cord; Spinal Cord Injuries

Spinal cord injury (SCI) is known as a debilitating condition which usually occurs due to traumas to the spine. However, the injury could also occur during clinical interventions such as spinal deformity and thoracoabdominal aortic surgeries. Intraoperative cord compression and ischemia are considered the mechanisms of primary injury in this regard. In the current study, we aimed to evaluate the therapeutic effects of minocycline, a promising agent for post-injury treatment, prophylactic administration. In a rat model of SCI through contusion injury, T9 vertebra laminectomy was performed on 40 Sprague-Dawley male rats provided from Pasteur Institute (Tehran, Iran). The reason behind selecting only male rats in our study was the fact that menstrual cycle of female rats affects healing process. Rodents were divided into a sham-operated group, a control group receiving only saline, a minocycline-treated group, and a minocycline pretreated group. Locomotor scaling, behavioral tests for neuropathic pain, and weight changes were evaluated and compared through a 28-days period. At the end of the study, tissue samples were taken to assess neuroinflammatory cytokine and histopathological changes. Minocycline pretreatment was as effective as its post-SCI administration regarding locomotor activity recovery, mechanical pain, and thermal allodynia. Furthermore, spinal cord inflammation and histopathological alterations were both similar in pretreatment and treatment groups indicating substantially better status. None of the treatments could have completely restore or prevent the spinal cord damage. Minocycline pretreatment can show promising therapeutic effects similar to its post-injury administration, inhibiting inflammatory microglial activity.

Topics: Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Cytokines; Locomotion; Male; Minocycline; Neuralgia; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries

Spinal cord injury (SCI) is an important health problem, and there is no universal treatment protocol for it today. Following SCI pro-inflammatory mediators such as tumor necrosis factor- alpha (TNF-α) and interleukin-6 (IL-6) increase at the lesion site and play important roles in secondary tissue damage. Methylprednisolone (MP) is a glucocorticoid, and minocycline is a tetracycline-derived antibiotic both with neuroprotective effects on central nervous system trauma. However, there are limited studies on their effects on SCI. In this study, we aimed to evaluate effects of MP+minocycline combined treatment on cellular distribution and localization of TNF-α And IL-6 after SCI. Eighty Wistar rats were divided into three main groups as the intact control group, sham operation group, and experimental control group that received spinal cord compression injury. Following the injury, the experimental control group was subdivided into four groups as control, methylprednisolone treatment, minocycline treatment and, MP+minocycline combined treatment groups. Tissue samples were obtained from all groups at 24 hours and 72 hours after the injury. We found a significant decrease in TNF-α And IL-6 expressions in combined treatment group at 24 hours after injury. Also, there was a significant decrease in MDA and increase in SOD levels in this group. Furthermore, decreased lipid peroxidation and neuronal and glial cell death were also observed in combined treatment group. These results suggest that MP+minocycline combined treatment promotes functional recovery and, it should be considered as an effective treatment protocol following SCI.

Topics: Animals; Anti-Inflammatory Agents; Disease Models, Animal; Interleukin-6; Methylprednisolone; Minocycline; Neuroprotective Agents; Rats; Rats, Wistar; Recovery of Function; Spinal Cord Injuries; Tumor Necrosis Factor-alpha

Topics: Animals; Gliosis; Hindlimb; Minocycline; Neurons; Rats; Spinal Cord Injuries

Spinal cord injury (SCI) routinely causes the immediate loss and disruption of neurons followed by complicated secondary injuries, including inflammation, oxidative stress, and dense glial scar formation. Inhibitory factors in the lesion scar and poor intrinsic neural regeneration capacity restrict functional recovery after injury. Minocycline, which has neuroprotective activity, can alleviate secondary injury, but the long-term administration of this drug may cause toxicity. Polysialic acid (PSA) is a large cell-surface carbohydrate that is critical for central nervous system development and is capable of promoting precursor cell migration, axon path finding, and synaptic remodeling; thus, PSA plays a vital role in tissue repair and regeneration. Here, we developed a PSA-based minocycline-loaded nanodrug delivery system (PSM) for the synergistic therapy of spinal cord injury. The prepared PSM exerted marked anti-inflammatory and neuroprotective activities both in vitro and in vivo. The administration of PSM could significantly protect neurons and myelin sheaths from damage, reduce the formation of glial scar, recruit endogenous neural stem cells to the lesion site, and promote the regeneration of neurons and the extension of long axons throughout the glial scar, thereby largely improving the locomotor function of SCI rats and exerting a superior therapeutic effect. The findings might provide a novel strategy for SCI synergistic therapy and the utilization of PSA in other central nervous system diseases.

Topics: Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Drug Carriers; Micelles; Minocycline; Nerve Regeneration; Neurons; Neuroprotective Agents; Rats; Sialic Acids; Spinal Cord Injuries

Opioids are among the most effective and widely prescribed medications for the treatment of pain following spinal cord injury (SCI). Spinally-injured patients receive opioids within hours of arrival at the emergency room, and prolonged opioid regimens are often employed for the management of post-SCI chronic pain. However, previous studies in our laboratory suggest that the effects of opioids such as morphine may be altered in the pathophysiological context of neurotrauma. Specifically, we have shown that morphine administration in a rodent model of SCI increases mortality and tissue loss at the injury site, and decreases recovery of motor and sensory function, and overall health, even weeks after treatment. The literature suggests that opioids may produce these adverse effects by acting as endotoxins and increasing glial activation and inflammation. To better understand the effects of morphine following SCI, in this study we used flow cytometry to assess immune-competent cells at the lesion site. We observed a morphine-induced increase in the overall number of CD11b+ cells, with marked effects on microglia, in SCI subjects. Next, to investigate whether this increase in the inflammatory profile is necessary to produce morphine's effects, we challenged morphine treatment with minocycline. We found that pre-treatment with minocycline reduced the morphine-induced increase in microglia at the lesion site. More importantly, minocycline also blocked the adverse effects of morphine on recovery of function without disrupting the analgesic efficacy of this opioid. Together, our findings suggest that following SCI, morphine may exacerbate the inflammatory response, increasing cell death at the lesion site and negatively affecting functional recovery.

Topics: Analgesics, Opioid; Animals; Inflammation; Macrophages; Male; Microglia; Minocycline; Morphine; Pain; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord; Spinal Cord Injuries

We tested a biomaterial-based approach to preserve the critical phrenic motor circuitry that controls diaphragm function by locally delivering minocycline hydrochloride (MH) following cervical spinal cord injury (SCI). MH is a clinically-available antibiotic and anti-inflammatory drug that targets a broad range of secondary injury mechanisms via its anti-inflammatory, anti-oxidant and anti-apoptotic properties. However, MH is only neuroprotective at high concentrations that cannot be achieved by systemic administration, which limits its clinical efficacy. We have developed a hydrogel-based MH delivery system that can be injected into the intrathecal space for local delivery of high concentrations of MH, without damaging spinal cord tissue. Implantation of MH hydrogel after unilateral level-C4/5 contusion SCI robustly preserved diaphragm function, as assessed by in vivo recordings of compound muscle action potential (CMAP) and electromyography (EMG) amplitudes. MH hydrogel also decreased lesion size and degeneration of cervical motor neuron somata, demonstrating its central neuroprotective effects within the injured cervical spinal cord. Furthermore, MH hydrogel significantly preserved diaphragm innervation by the axons of phrenic motor neurons (PhMNs), as assessed by both detailed neuromuscular junction (NMJ) morphological analysis and retrograde PhMN labeling from the diaphragm using cholera toxin B (CTB). In conclusion, our findings demonstrate that local MH hydrogel delivery to the injured cervical spinal cord is effective in preserving respiratory function after SCI by protecting the important neural circuitry that controls diaphragm activation.

Topics: Animals; Cervical Cord; Diaphragm; Disease Models, Animal; Drug Delivery Systems; Female; Hydrogels; Minocycline; Nerve Net; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Recovery of Function; Respiration; Spinal Cord Injuries

Spinal cord injury (SCI) leads to immediate disruption of neuronal membranes and loss of neurons, followed by extensive secondary injury process. Treatment of SCI still remains a tremendous challenge clinically. Minocycline could target comprehensive secondary injury via anti-inflammatory, anti-oxidant and anti-apoptotic mechanisms. Polyethylene glycol (PEG), a known sealing agent, is able to seal the damaged cell membranes and reduce calcium influx, thereby exerting neuroprotective capacity. Here, an E-selectin-targeting sialic acid - polyethylene glycol - poly (lactic-co-glycolic acid) (SAPP) copolymer was designed for delivering hydrophobic minocycline to achieve combinational therapy of SCI. The obtained SAPP copolymer could self-assemble into micelles with critical micelle concentration being of 13.40 μg/mL, and effectively encapsulate hydrophobic minocycline. The prepared drug-loaded micelles (SAPPM) displayed sustained drug release over 72 h, which could stop microglia activation and exhibited excellent neuroprotective capacity in vitro. The SAPP micelles were efficiently accumulated in the lesion site of SCI rats via the specific binding between sialic acid and E-selectin. Due to the targeting distribution and combinational effect between PEG and minocycline, SAPPM could obviously reduce the area of lesion cavity, and realize more survival of axons and myelin sheaths from the injury, thus distinctly improving hindlimb functional recovery of SCI rats and conferring superior therapeutic effect in coparison with other groups. Our work presented an effective and safe strategy for SCI targeting therapy. Besides, neuroprotective capacity of PEG deserves further investigation on other central nervous system diseases.

Topics: Animals; Combined Modality Therapy; Female; Human Umbilical Vein Endothelial Cells; Humans; Mice; Micelles; Microglia; Minocycline; Myelin Sheath; N-Acetylneuraminic Acid; Neuroprotective Agents; Polyethylene Glycols; Polylactic Acid-Polyglycolic Acid Copolymer; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries

Spinal cord injury (SCI) is a complex condition, with limited therapeutic options, that results in sensory and motor disabilities. To boost discovery of novel therapeutics, we designed a simple and efficient drug screening platform. This innovative approach allows to determine locomotor rescue properties of small molecules in a zebrafish (Danio rerio) larval spinal cord transection model. We validated our screening platform by showing that Riluzole and Minocycline, two molecules that are in clinical trials for SCI, promote rescue of the locomotor function of the transected larvae. Further validation of the platform was obtained through the blind identification of D-Cycloserine, a molecule scheduled to enter phase IV clinical trials for SCI. Importantly, we identified Tranexamic acid and further showed that this molecule maintains its locomotor recovery properties in a rodent female contusion model. Our screening platform, combined with drug repurposing, promises to propel the rapid translation of novel therapeutics to improve SCI recovery in humans.

Topics: Animals; Cycloserine; Disease Models, Animal; Drug Discovery; Drug Evaluation, Preclinical; Female; Locomotion; Mice; Mice, Inbred C57BL; Minocycline; Riluzole; Spinal Cord Injuries; Tranexamic Acid; Zebrafish

Spinal cord injury (SCI) is a devastating neurological condition for which there is no effective treatment to restore neurological function. The development of new treatments for those with SCI may be hampered by the insensitivity of clinical tools to assess motor function in humans. Treatments aimed at preserving neuronal function through anti-inflammatory pathways (i.e., neuroprotection) have been a mainstay of pre-clinical SCI research for decades. Minocycline, a clinically available antibiotic agent with anti-inflammatory properties, has demonstrated promising neuroprotective effects in a variety of animal models and improved motor recovery in a Phase-2 human trial. Here, we leveraged our recently developed T3 severe contusion model in the rat to determine the ability of minocycline to preserve descending sympathoexcitatory axons and improve cardiovascular control after SCI. Forty-one male Wistar rats were randomized to either a treatment group (minocycline; n = 20) or a control group (vehicle; n = 21). All rats received a severe T3 contusion. Minocycline (or vehicle) was administered intraperitoneally at one hour post-injury (90 mg/kg), then every 12 h for two weeks (45 mg/kg). Neuroanatomical correlates (lesion area, descending sympathoexcitatory axons) were assessed, in addition to an assessment of cardiovascular control (hemodynamics, autonomic dysreflexia) and motor behavior. Here, we show that minocycline reduces lesion area, increases the number of descending sympathoexctitatory axons traversing the injury site, and ultimately reduces the severity of autonomic dysreflexia. Finally, we show that autonomic dysreflexia is a more sensitive marker of treatment stratification than motor function.

Topics: Animals; Anti-Inflammatory Agents; Autonomic Dysreflexia; Disease Models, Animal; Male; Minocycline; Neuroprotective Agents; Random Allocation; Rats; Rats, Wistar; Spinal Cord; Spinal Cord Injuries

Traumatic spinal cord injury (SCI) represents a significant burden of illness, but it is relatively uncommon and heterogeneous, making it challenging to achieve sufficient subject enrollment in clinical trials of therapeutic interventions for acute SCI. The Rick Hansen Spinal Cord Injury Registry (RHSCIR) is a national SCI Registry that enters patients with SCI from acute-care centers across Canada. To predict the feasibility of conducting clinical trials of acute SCI within Canada, we have applied the inclusion/exclusion criteria of six previously conducted SCI trials to the RHSCIR data set and generated estimates of how many Canadian persons would have been eligible theoretically for enrollment in these studies. Data for SCI cases were prospectively collected for RHSCIR at 18 acute and 13 rehabilitation sites across Canada. RHSCIR patients enrolled between 2009-2013 who met the following key criteria were included: non-penetrating traumatic SCI; received acute care at a RHSCIR site; age more than 18, less than 75 years, and had complete admission single neurological level of injury data. Inclusion and exclusion criteria for the Minocycline in Acute Spinal Cord injury (Minocycline), Riluzole, Surgical Timing in Acute Spinal Cord Injury Study (STASCIS), Cethrin, Nogo antibody study (NOGO), and Sygen studies were applied retrospectively to this data set. The numbers of patients eligible for each clinical trial were determined. There were 2166 of the initial 2714 patients (79.8%) who met the key criteria and were included in the data set. Projected annual numbers of eligible patients for each trial were: Minocycline, 117; Riluzole, 62; STASCIS, 109; Cethrin, 101; NOGO, 82; and Sygen, 70. An additional 8.0% of the sample had a major head injury (Glasgow Coma Scale [GCS] score ≤12) and would have been excluded from the trials. RHSCIR provides a comprehensive national data set that may serve as a useful tool in the planning of multicenter clinical SCI trials.

Topics: Adult; Aged; Canada; Databases, Factual; Feasibility Studies; Female; Forecasting; Humans; Male; Middle Aged; Minocycline; Patient Selection; Prospective Studies; Randomized Controlled Trials as Topic; Registries; Retrospective Studies; Riluzole; Spinal Cord Injuries; Young Adult

Many mechanisms contribute to the secondary injury cascades following traumatic spinal cord injury (SCI). However, most current treatment strategies only target one or a few elements in the injury cascades, and have been largely unsuccessful in clinical trials. Minocycline hydrochloride (MH) is a clinically available antibiotic and anti-inflammatory drug that has been shown to target a broad range of secondary injury mechanisms via its anti-inflammatory, anti-oxidant, and anti-apoptotic properties. However, MH is only neuroprotective at high concentrations. The inability to translate the high doses of MH used in experimental animals to tolerable doses in human patients limits its clinical efficacy. In addition, the duration of MH treatment is limited because long-term systemic administration of high doses of MH has been shown to cause liver toxicity and even death. We have developed a drug delivery system in the form of hydrogel loaded with polysaccharide-MH complexes self-assembled by metal ions for controlled release of MH. This drug delivery system can be injected into the intrathecal space for local delivery of MH with sufficient dose and duration, without causing any additional tissue damage. We show that local delivery of MH at a dose that is lower than the standard human dose (3 mg/kg) was more effective in reducing secondary injury and promoting locomotor functional recovery than systemic injection of MH with the highest dose and duration reported in experimental animal SCI (90-135 mg/kg).

Topics: Animals; Crystallization; Drug Implants; Female; Hydrogels; Ions; Metal Nanoparticles; Minocycline; Nanocapsules; Nerve Regeneration; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries; Treatment Outcome

The objective of this study is to investigate the fate of albumin coupled nanoparticulate system over non-targeted drug carrier in the treatment of hemisectioned spinal cord injury (SCI).. Targeted delivery of methyl prednisolone (MP) and minocycline (MC) portrayed improved therapeutic efficacy as compared with non-targeted nanoparticles (NPS).. Albumin coupled, chitosan stabilized, and cationic NPS (albumin-MP + MC - NPS) of poly-(lactide-co-glycolic acid) were prepared using the emulsion solvent evaporation method. Prepared NPS were characterized for drug entrapment efficiency, particle size, poly-dispersity index (PDI), zeta potential, and morphological characteristics. Their evaluation was done based on the pharmaceutical, toxicological, and pharmacological parameters.. In vitro release of MP + MC from albumin-MP + MC - NPS and MP + MC - NPS was observed to be very controlled for the period of eight days. Cell viability study portrayed non-toxic nature of the developed NPS. Albumin-MP + MC - NPS showed prominent anti-inflammatory potential as compared with non-targeted NPS (MP + MC - NPS) when studied in LPS-induced inflamed astrocytes. Albumin-MP + MC - NPS reduced lesional volume and improved behavioral outcomes significantly in rats with SCI (hemisectioned injury model) when compared with that of MP + MC - NPS.. Albumin-coupled NPS carrier offered an effective method of SCI treatment following safe co-administration of MP and MC. The in vitro and in vivo effectiveness of MP + MC was improved tremendously when compared with the effectiveness showed by MP + MC - NPS. That could be attributed to the site specific, controlled release of MP + MC to the inflammatory site.

Topics: Albumins; Animals; Anti-Inflammatory Agents; Astrocytes; Behavior, Animal; Cell Survival; Chitosan; Drug Carriers; Drug Combinations; Drug Delivery Systems; Female; Lactic Acid; Methylprednisolone; Minocycline; Nanoparticles; Particle Size; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries

Many efforts have been performed in order to understand the role of recruited macrophages in the progression of spinal cord injury (SCI). Different studies revealed a pleiotropic effect played by these cells associated to distinct phenotypes (M1 and M2), showing a predictable spatial and temporal distribution in the injured site after SCI. Differently, the role of activated microglia in injury progression has been poorly investigated, mainly because of the challenges to target and selectively modulate them in situ. A delivery nanovector tool (poly-ε-caprolactone-based nanoparticles) able to selectively treat/target microglia has been developed and used here to clarify the temporal and spatial involvement of the pro-inflammatory response associated to microglial cells in SCI. We show that a treatment with nanoparticles loaded with minocycline, the latter a well-known anti-inflammatory drug, when administered acutely in a SCI mouse model is able to efficiently modulate the resident microglial cells reducing the pro-inflammatory response, maintaining a pro-regenerative milieu and ameliorating the behavioral outcome up to 63 days post injury. Furthermore, by using this selective delivery tool we demonstrate a mechanistic link between early microglia activation and M1 macrophages recruitment to the injured site via CCL2 chemokine, revealing a detrimental contribution of pro-inflammatory macrophages to injury progression after SCI.

Topics: Animals; Behavior, Animal; Cell Movement; Chemokine CCL2; Disease Models, Animal; Disease Progression; Inflammation; Macrophages; Mice, Inbred C57BL; Microglia; Minocycline; Models, Biological; Nanoparticles; Nerve Regeneration; Phenotype; Polyesters; Spinal Cord Injuries

Injury to the spinal cord results in immediate physical damage (primary injury) followed by a prolonged posttraumatic inflammatory disorder (secondary injury). The present study aimed to investigate the neuroprotective effects of minocycline and FK506 (Tacrolimus) individually and in combination on recovery from experimental spinal cord injury (SCI). Young adult male rats were subjected to experimental SCI by weight compression method. Minocycline (50mg/kg) and FK506 (1mg/kg) were administered orally in combination and individually to the SCI group daily for three weeks. During these three weeks, the recovery was measured using behavioral motor parameters (including BBB, Tarlov and other scorings) every other day for 29days after SCI. Thereafter, the animals were sacrificed and the segment of the spinal cord centered at the injury site was removed for the histopathological studies as well as for biochemical analysis of monoamines such as 5-hydroxytryptamine (5-HT) and 5-hydroxy-indolacetic acid (5-HIAA) and some oxidative stress indices, such as thiobarbituric acid-reactive substances (TBARS), total glutathione (GSH) and myeloperoxidase (MPO). All behavioral results indicated that both drugs induced significant recovery from SCI with respect to time. The biochemical and histopathological results supported the behavioral findings, revealing significant recovery in the regeneration of the injured spinal tissues, the monoamine levels, and the oxidative stress indices. Overall, the effects of the tested drugs for SCI recovery were as follows: FK506+minocycline>minocycline>FK506 in all studied parameters. Thus, minocycline and FK506 may prove to be a potential therapy cocktail to treat acute SCI. However, further studies are warranted.

Topics: Animals; Biogenic Monoamines; Drug Therapy, Combination; Gait; Glutathione; Lipid Peroxidation; Locomotion; Male; Minocycline; Neuroprotective Agents; Oxidative Stress; Peroxidase; Rats; Recovery of Function; Spinal Cord Injuries; Tacrolimus

The effects of minocycline on neuronal injury after spinal cord injury (SCI) are limited and controversial. Therefore we aimed to investigate the protective effects of minocycline on tissue and on serum concentrations of malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, tissue total antioxidant and oxidant status (TAS and TOS, respectively), and AST and LDH levels in rats with SCI.. This study was performed on 7-8 weeks 38 male Wistar albino rats. The animals were randomly divided into five groups: group 1, Sham (n=8); group 2, SCI (spinal cord injury)/control (n=8); group 3, SCI+minocycline3 (n=7); group 4, SCI+minocycline30 (n=8) and group 5 SCI+minocycline90 (n=7). Blood and tissue samples were analysed for MDA, SOD, GSH-Px, TAS, TOS, AST and LDH levels.. The MDA levels were significantly higher in SCI group compared to sham group (p<0.001), and MDA levels were also significantly higher in SCI group compared to SCI+M3, SCI+M30, SCI+M90 (p<0.05). SOD levels were significantly higher in SCI+M30 when compared to SCI and SCI+M3 groups (p<0.05). GSH-Px levels decreased significantly in SCI and SCI+M3 groups compared to sham (p<0.05). SCI+M3 group showed significantly decreased levels of TAS and TOS compared to SCI group (p<0.05). TAS and TOS levels significantly increased in SCI+M90 group compared to SCI+M3 and SCI+M30 groups (p<0.05).. The present study demonstrates the dose-dependent antioxidant activity of minocycline against spinal cord injury in rats. Minocycline administration increased antioxidant enzyme levels and improved total antioxidant status.

Topics: Animals; Antioxidants; Disease Models, Animal; Free Radical Scavengers; Male; Malondialdehyde; Minocycline; Neuroprotective Agents; Oxidative Stress; Rats; Rats, Wistar; Spinal Cord; Spinal Cord Injuries

The aims of this study were to assess that the effects of bone marrow mesenchymal stem cells (BMSCs) combination with minocycline improve spinal cord injury (SCI) in rat model. In the present study, the Wistar rats were randomly divided into five groups: control group, SCI group, BMSCs group, Minocycline group and BMSCs + minocycline group. Basso, Beattie and Bresnahan (BBB) test and MPO activity were used to assess the effect of combination therapy on locomotion and neutrophil infiltration. Inflammation factors, VEGF and BDNF expression, caspase-3 activation, phosphorylation-p38MAPK, proNGF, p75NTR and RhoA expressions were estimated using commercial kits or western blot, respectively. BBB scores were significantly increased and MPO activity was significantly undermined by combination therapy. In addition, combination therapy significantly decreased inflammation factors in SCI rats. Results from western blot showed that combination therapy significantly up-regulated the protein of VEGF and BDNF expression and down-regulated the protein of phosphorylation-p38MAPK, proNGF, p75NTR and RhoA expressions in SCI rats. Combination therapy stimulation also suppressed the caspase-3 activation in SCI rats. These results demonstrated that the effects of bone marrow mesenchymal stem cells combination with minocycline improve SCI in rat model.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Blotting, Western; Bone Marrow Transplantation; Disease Models, Animal; Female; Male; Mesenchymal Stem Cell Transplantation; Minocycline; Rats; Rats, Sprague-Dawley; Rats, Wistar; Recovery of Function; Spinal Cord Injuries

Spinal root avulsion produces tactile and thermal hypersensitivity, neurodegeneration, and microglial and astrocyte activation in both the deafferented and the adjacent intact spinal cord segments. Following avulsion of the fifth lumbar spinal root, immediate and prolonged treatment with riluzole or minocycline for 2 weeks altered the development of behavioral hypersensitivity. Riluzole delayed the onset of thermal and tactile hypersensitivity and partially reversed established pain behavior. Minocycline effectively prevented and reversed both types of behavioral change. Histologic analysis revealed that both drugs reduced microglial staining in the spinal cord, with minocycline being more effective than riluzole. Astrocyte activation was ameliorated to a lesser extent. Surprisingly, neither drug provided a neuroprotective effect on avulsed motoneurons.. Immediate treatment of spinal root avulsion injuries with minocycline or riluzole prevents the onset of evoked pain hypersensitivity by reducing microglial cell activation. When treatment is delayed, minocycline, but not riluzole, reverses pre-established hypersensitivity. Thus, these drugs may provide a new translational treatment option for chronic avulsion injury pain.

Topics: Animals; Disease Models, Animal; Functional Laterality; Hyperalgesia; Male; Minocycline; Neurons; Neuroprotective Agents; Pain; Pain Threshold; Phosphopyruvate Hydratase; Rats; Rats, Wistar; Riluzole; Spinal Cord Injuries; Spinal Nerve Roots; Time Factors

Much evidence shows that acute and chronic inflammation in spinal cord injury (SCI), characterized by immune cell infiltration and release of inflammatory mediators, is implicated in development of the secondary injury phase that occurs after spinal cord trauma and in the worsening of damage. Activation of microglia/macrophages and the associated inflammatory response appears to be a self-propelling mechanism that leads to progressive neurodegeneration and development of persisting pain state. Recent advances in polymer science have provided a huge amount of innovations leading to increased interest for polymeric nanoparticles (NPs) as drug delivery tools to treat SCI. In this study, we tested and evaluated in vitro and in vivo a new drug delivery nanocarrier: minocycline loaded in NPs composed by a polymer based on poly-ε-caprolactone and polyethylene glycol. These NPs are able to selectively target and modulate, specifically, the activated proinflammatory microglia/macrophages in subacute progression of the secondary injury in SCI mouse model. After minocycline-NPs treatment, we demonstrate a reduced activation and proliferation of microglia/macrophages around the lesion site and a reduction of cells with round shape phagocytic-like phenotype in favor of a more arborized resting-like phenotype with low CD68 staining. Treatment here proposed limits, up to 15 days tested, the proinflammatory stimulus associated with microglia/macrophage activation. This was demonstrated by reduced expression of proinflammatory cytokine IL-6 and persistent reduced expression of CD68 in traumatized site. The nanocarrier drug delivery tool developed here shows potential advantages over the conventionally administered anti-inflammatory therapy, maximizing therapeutic efficiency and reducing side effects.

Topics: Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Biocompatible Materials; Cell Survival; Coculture Techniques; Disease Models, Animal; Drug Delivery Systems; Enzyme-Linked Immunosorbent Assay; Hydrogels; Inflammation; Interleukin-6; Macrophages; Mice; Mice, Inbred C57BL; Microglia; Minocycline; Nanomedicine; Nanoparticles; Polyesters; Polyethylene Glycols; Polymers; Quantum Dots; Rhodamines; Spinal Cord; Spinal Cord Injuries

Topics: Humans; Minocycline; Randomized Controlled Trials as Topic; Spinal Cord Injuries

A prospective, randomized experimental research.. To evaluate the short- and long-term neuroprotective effects of minocycline on the secondary injury process of an experimental traumatic spinal cord injury (SCI) model.. Traumatic SCI is a devastating problem of health that results in high morbidity and mortality rates. The loss of function after SCI results from both the primary mechanical insult and the subsequent, multifaceted secondary response.. A total of 80 adult male Spraque-Dawley rats (breeded by the Baskent University Animal Research Center) were randomly divided into 4 groups. A T10 contusion injury was produced by using modified Allen technique in all groups except the control group. No medication was administered to the rats in the trauma group. Minocycline was administered intraperitoneally and intravenously to the treatment groups. Short-term and/or long-term neuroprotective effects of minocycline on the lipid peroxidation (malondialdehyde, glutathione), apoptosis (terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling), ultrastructure of spinal cord (tissue electron microscopy), and behavioral assessments (Basso-Beattie-Bresnahan) were evaluated.. As compared with the trauma group, tissue malondialdehyde and glutathione levels demonstrated that minocycline significantly diminishes lipid peroxidation. Electromicroscopic study showed that minocycline preserves the ultrastructure of spinal cord tissue in the early post-traumatic period. Minocycline treatment significantly reduced the number of terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling positive cells both 1 day and 28 days after SCI. Behavioral assessments showed significant improvement in the hind limb functions of minocycline receiving rats starting 7 days after the SCI. Any statistically significant difference was not found between intraperitoneal or intravenous routes for minocycline injection.. Minocycline is neuroprotective and contributes to functional improvement after traumatic SCI by eliminating the destructive process of secondary injury. Having both satisfying anti-inflammatory and antiapoptotic effects in experimental models, it promises to be of therapeutic use in human SCI.

Topics: Animals; Apoptosis; Disease Models, Animal; Hindlimb; Humans; Infusions, Intravenous; Infusions, Parenteral; Lipid Peroxidation; Male; Microscopy, Electron, Transmission; Minocycline; Motor Activity; Neuroprotective Agents; Prospective Studies; Random Allocation; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord; Spinal Cord Injuries

Topics: Female; Humans; Male; Minocycline; Recovery of Function; Spinal Cord Injuries

An in vivo study in a rat model of acute spinal cord contusion.. To assess the efficacy of novel therapies for acute spinal cord injury (SCI), methods to evaluate accurately the effects of these therapies should be developed. Although neurological examination is commonly used for this purpose, unstable clinical conditions and the spontaneous recovery of neurological function in the acute and subacute phases after injury make this measurement unreliable. Recent studies have reported that the phosphorylated form of the high-molecular-weight neurofilament subunit NF-H (pNF-H), a new biomarker for axonal degeneration, can be measured in serum samples in experimental SCI animals. Therefore, we aimed to investigate the use of plasma pNF-H as an indicator of the efficacy of minocycline, a neuroprotective drug, for treating SCI.. This study was carried out at Saitama, Japan.. Spinal cord injured rats received either minocycline or saline intraperitoneally. The plasma pNF-H levels and functional hind limb score were determined after the injury.. Minocycline treatment reduced plasma pNF-H levels at 3 and 4 days post-injury (dpi). Rats with lower plasma pNF-H levels at 3 dpi had higher hind limb motor score at 28 dpi.. pNF-H levels may serve as a biomarker for evaluating the efficacy of therapies for SCI.

Topics: Animals; Biomarkers; Disease Models, Animal; Minocycline; Neurofilament Proteins; Neuroprotective Agents; Phosphorylation; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries

Our previous data suggested that ongoing inflammation in the spinal cord 6 weeks following spinal cord injury was detrimental to locomotor function. Others have shown in the acute and sub-acute post-injury phase that microglial/macrophage activation and T regulatory cells are detrimental to recovery. Here, C57BL/6 mice with a moderately severe T9 contusion were injected intravenously daily with minocycline, which reduces microglial/macrophage activation, or with CD25 antibodies, which reduce T regulatory cell function, starting at 6 weeks after injury. Both anti-inflammatory drugs caused an improvement in hindlimb locomotor function over the 2-week treatment, as measured by the Basso Mouse Scale (BMS). The improvement was functionally important, with mice having problems with coordinated stepping (BMS ∼6) before treatment to walking essentially normally (BMS >7) at the end of the treatment. The effects diminished within 1 week after termination of the treatments, suggesting an ongoing and dynamic inflammatory process. The area of white matter or the inflammatory markers CD68 for activated microglia/macrophages and CD45 for leukocytes were not different between the groups. These data suggest that inflammation during the chronic phase following spinal cord injury reduces conduction through the epicenter, possibly by release of cytokines, and is amenable to treatment for improved neurological function.

Topics: Animals; Anti-Inflammatory Agents; Female; Interleukin-2 Receptor alpha Subunit; Macrophages; Mice; Microglia; Minocycline; Motor Activity; Nerve Fibers, Myelinated; Recovery of Function; Spinal Cord; Spinal Cord Injuries; T-Lymphocytes, Regulatory

We tested whether reducing macrophage infiltration would improve the survival of allogeneic bone marrow stromal cells (BMSC) transplanted in the contused adult rat thoracic spinal cord. Treatment with cyclosporine, minocycline, or methylprednisolone all resulted in a significant decrease in macrophage infiltration at 3 days postinjury. However, when BMSC were injected at that time point, survival 7 days later was similar between treatment groups and saline-injected controls. In fact, we found that the presence of BMSC resulted in a significant increase in macrophage infiltration into the contusion.

Topics: Animals; Bone Marrow Transplantation; Cyclosporine; Female; Graft Survival; Immunohistochemistry; Immunosuppressive Agents; Macrophages; Methylprednisolone; Minocycline; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries; Stromal Cells

Minocycline, a commonly prescribed tetracycline antibiotic, has shown promise as a potential therapeutic agent in animal models of numerous neurologic disorders such as amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Huntington's disease, stroke, and spinal cord injury (SCI). Simvastatin is one of many hydroxymethylglutaryl-coenzyme-A reductase inhibitors prescribed to lower cholesterol. These drugs are also known to reduce inflammation and oxidative stress, improve endothelial function, and modulate the immune system in stroke, traumatic brain injury, and SCI. As both drugs have translational potential, we evaluated their neuroprotective properties here in a clinically relevant model of contusive cervical spinal cord injury. Sprague-Dawley rats underwent a unilateral cervical contusion SCI at C5 and were randomized to receive: 1. Minocycline 90 mg/kg x 3 days, 2. Simvastatin 20 mg/kg x 7 days, 3. Simvastatin 20 mg/kg x 7 days then 5mg/kg x 35 days, or 4. Saline (Control). Behavioral recovery was assessed over 6 weeks using the horizontal ladder test, cylinder rearing test, modified Montoya staircase test and grooming test. Forepaw sensitivity was also assessed using the electronic von Frey Aesthesiometer. The corticospinal and rubrospinal tracts were traced and the spinal cords were harvested 7 weeks after injury. The extent of gray matter and white matter sparing and corticospinal and rubrospinal tract sprouting were evaluated in cross sections of the spinal cord. In the end, neither minocycline nor simvastatin treatment was associated with improved performance on the behavioral tests, as compared to saline controls. Performance on the horizontal ladder test, cylinder rearing test, and von Frey sensory test were similar among all groups. Animals treated for 42 days with simvastatin scored significantly higher in the grooming score compared to other groups, but retrieved significantly fewer pellets on the modified Montoya staircase test than control and minocycline treated animals. Histologically, there were no significant differences in white and gray matter sparing and in the extent of corticospinal and rubrospinal sprouting between the four groups. In conclusion, both minocycline and simvastatin failed to improve functional and histological recovery in our model of contusive cervical spinal cord injury.

Topics: Animals; Cervical Vertebrae; Disease Models, Animal; Drug Therapy, Combination; Minocycline; Myelitis; Nerve Regeneration; Neuroprotective Agents; Oxidative Stress; Random Allocation; Rats; Rats, Sprague-Dawley; Recovery of Function; Simvastatin; Spinal Cord Injuries; Treatment Failure

Topics: Animals; Clinical Laboratory Techniques; Disease Models, Animal; Gastrointestinal Hormones; Ghrelin; Humans; Mice; Minocycline; Plant Extracts; Reproducibility of Results; Rodentia; Scutellaria baicalensis; Spinal Cord Injuries

Loss of function is usually considered the major consequence of spinal cord injury (SCI). However, pain severely compromises the quality of life in nearly 70% of SCI patients. The principal aim of this study was to assess the contribution of Tumor necrosis factor alpha (TNF-alpha) to SCI pain. TNF-alpha blockers have already been successfully used to treat inflammatory disorders but there are few studies on its effect on neuropathic pain, especially following SCI. Following T13 spinal cord hemisection, we examined the effects on mechanical allodynia and microglial activation of immediate and delayed chronic intrathecal treatment with etanercept, a fusion protein blocker of TNF-alpha. Immediate treatment (starting at the time of injury) with etanercept resulted in markedly reduced mechanical allodynia 1, 2, 3 and 4 weeks after SCI. Delayed treatment had no effect. Immediate etanercept treatment also reduced spinal microglial activation assessed by OX-42 immunostaining, a putative marker of activated microglia. To assess whether the effects of etanercept were mediated via decreased microglial activation, we examined the effects of the microglial inhibitor, minocycline which significantly reduced the development of pain behaviours at 1 and 2 weeks after SCI compared to saline treatment. Minocycline also significantly reduced microglial OX-42 expression. Furthermore, minocycline decreased the expression of noxious-stimulation-induced c-Fos, suggesting an effect on evoked neuronal activity. This study demonstrates that TNF-alpha plays an important role in the establishment of neuropathic pain following SCI, seemingly dependent on microglial activation. Pharmacological targeting of TNF-alpha may offer therapeutic opportunities for treating SCI pain.

Topics: Animals; Anti-Bacterial Agents; Cell Count; Etanercept; Functional Laterality; Hot Temperature; Immunoglobulin G; Immunohistochemistry; Immunosuppressive Agents; Injections, Spinal; Male; Microglia; Minocycline; Pain; Physical Stimulation; Proto-Oncogene Proteins c-fos; Rats; Rats, Wistar; Receptors, Tumor Necrosis Factor; Signal Transduction; Spinal Cord Injuries; Tumor Necrosis Factors

Spinal cord injury (SCI) results in the development of chronic pain syndromes that can persist indefinitely and cause reductions in quality of life. Treatment of chronic pain after SCI remains extremely challenging; thus, an important research goal is to determine whether early treatments can attenuate the subsequent development of pain conditions. The current study examined the hypothesis that early administration of the microglial-inhibiting drug minocycline could ameliorate the development of pain after SCI. Adult male Sprague-Dawley rats underwent SCI at the ninth thoracic spinal segment and received either vehicle or minocycline treatment for 5 days postinjury. Time course studies revealed that over 4 weeks post-SCI, microglial activation in vehicle-treated animals was progressively increased. Minocycline treatment resulted in reduction, but not prevention, of microglial activation over time. Electrophysiological experiments showed that early minocycline administration attenuated the development of chronic hyperresponsiveness of lumbar dorsal horn neurons. Similarly, behavioral assessment showed that minocycline also resulted in increased pain thresholds. These results suggest that inhibition of early neuroimmune events can have a powerful impact on the development of long-term pain phenomena following SCI and support the conclusion that modulation of microglial signaling may provide a new therapeutic strategy for patients suffering from post-SCI pain.

Topics: Action Potentials; Animals; Anti-Bacterial Agents; Behavior, Animal; Male; Microglia; Minocycline; Pain; Pain Threshold; Rats; Rats, Sprague-Dawley; Reaction Time; Sensory Receptor Cells; Spinal Cord Injuries

This study was initiated due to an NIH "Facilities of Research--Spinal Cord Injury" contract to support independent replication of published studies that could be considered for a clinical trial in time. Minocycline has been shown to have neuroprotective effects in models of central nervous system injury, including in a contusive spinal cord injury (SCI) model at the thoracic level. Beneficial effects of minocycline treatment included a significant improvement in locomotor behavior and reduced histopathological changes [Lee, S.M., Yune, T.Y., Kim, S.J., Park, D.O.W., Lee, Y.K., Kim, Y.C., Oh, Y.J., Markelonis, G.J., Oh, T.H., 2003. Minocycline reduces cell death and improves functional recovery after traumatic spinal cord injury in the rat. J Neurotrauma. 20, 1017-1027.] To verify these important observations, we repeated this study in our laboratory. The NYU (MASCIS) Impactor was used to produce a moderate cord lesion at the vertebral level T9-T10 (height 12.5 mm, weight 10 g), (n=45), followed by administration of minocycline, 90 mg/kg (group 1: minocycline IP, n=15; group 2: minocycline IV, n=15; group 3: vehicle IP, n=8; group 4: vehicle IV, n=7) immediately after surgery and followed by two more doses of 45 mg/kg/IP at 12 h and 24 h. Open field locomotion (BBB) and subscores were examined up to 6 weeks after SCI and cords were processed for quantitative histopathological analysis. Administration of minocycline after SCI did not lead to significant behavioral or histopathological improvement. Although positive effects with minocycline have been reported in several animal models of injury with different drug administration schemes, the use of minocycline following contusive SCI requires further investigation before clinical trials are implemented.

Topics: Animals; Disease Models, Animal; Efferent Pathways; Lameness, Animal; Male; Minocycline; Motor Activity; Neuroprotective Agents; Paralysis; Rats; Rats, Sprague-Dawley; Recovery of Function; Reproducibility of Results; Spinal Cord; Spinal Cord Injuries; Thoracic Vertebrae; Treatment Failure

The over-expression of excitotoxic neurotransmitter, such as glutamate, is an important mechanism of secondary injury after spinal cord injury. The authors examined the neuroprotective effect of pregabalin (GP) which is known as to reduce glutamate secretion, in a rat model of spinal cord injury. Thirty-two male Sprague-Dawley rats were randomly allocated to four groups; the control group (contusion injury only), the methylprednisolone treated group, the minocycline treated group and the GP treated group. Spinal cord injury was produced by contusion using the New York University impactor (25 g-cm, at the 9th-10th thoracic). Functional evaluations were done using the inclined plane test and a motor rating scale. Anti-apoptotic and anti-inflammatory effects were evaluated by in situ nick-end labeling staining technique (TUNEL) and immunofluorescence staining of cord tissues obtained at 7 days post-injury. Pregabalin treated animals showed significantly better functional recovery, and anti-apoptotic and anti-inflammatory effects. Mean numbers of TUNEL positive cells in the respective groups were 63.5 +/- 7.4, 53.6 +/- 4.0, 44.2 +/- 3.9 and 36.5 +/- 3.6. Double staining (TUNEL and anti-CC1) for oligodendrocyte apoptosis, was used to calculate oligodendrocyte apoptotic indexes (AI), using the following formula AI = (No. of doubly stained cells/No. of anti-CC1 positive cells) x 100. Mean group AIs were 88.6, 46.7, 82.1 and 70.3%, respectively. Mean numbers of activated microglia (anti-OX-42 positive cells) in high power fields were 29.8 +/- 3.9, 22.7 +/- 4.1, 21.0 +/- 3.9 and 17.8 +/- 4.3, respectively. This experiment demonstrates that GP can act as a neuroprotector after SCI in rats, and its anti-apoptotic and anti-inflammatory effects are related to its neuroprotective effect. Further studies are needed to unveil the specific mechanism involved at the receptor level.

Topics: Analgesics; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Apoptosis; gamma-Aminobutyric Acid; Glutamic Acid; Inflammation; Male; Methylprednisolone; Microglia; Minocycline; Models, Animal; Pregabalin; Random Allocation; Rats; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries

Spinal cord injury (SCI) causes a permanent neurological disability, and no satisfactory treatment is currently available. After SCI, pro-nerve growth factor (proNGF) is known to play a pivotal role in apoptosis of oligodendrocytes, but the cell types producing proNGF and the signaling pathways involved in proNGF production are primarily unknown. Here, we show that minocycline improves functional recovery after SCI in part by reducing apoptosis of oligodendrocytes via inhibition of proNGF production in microglia. After SCI, the stress-responsive p38 mitogen-activated protein kinase (p38MAPK) was activated only in microglia, and proNGF was produced by microglia via the p38MAPK-mediated pathway. Minocycline treatment significantly reduced proNGF production in microglia in vitro and in vivo by inhibition of the phosphorylation of p38MAPK. Furthermore, minocycline treatment inhibited p75 neurotrophin receptor expression and RhoA activation after injury. Finally, minocycline treatment inhibited oligodendrocyte death and improved functional recovery after SCI. These results suggest that minocycline may represent a potential therapeutic agent for acute SCI in humans.

Topics: Analysis of Variance; Animals; Animals, Newborn; Anti-Bacterial Agents; Axons; Cell Death; Cells, Cultured; Disease Models, Animal; Gene Expression Regulation; In Situ Nick-End Labeling; Male; Minocycline; Motor Activity; Myelin Sheath; Nerve Growth Factors; Oligodendroglia; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Rho Factor; RNA, Messenger; Spinal Cord Injuries

Traumatic spinal cord injury (SCI) results not only in motor impairment but also in chronic central pain, which can be refractory to conventional treatment approaches. It has been shown recently that in models of peripheral nerve injury, spinal cord microglia can become activated and contribute to development of pain. Considering their role in pain after peripheral injury, and because microglia are known to become activated after SCI, we tested the hypothesis that activated microglia contribute to chronic pain after SCI. In this study, adult male Sprague Dawley rats underwent T9 spinal cord contusion injury. Four weeks after injury, when lumbar dorsal horn multireceptive neurons became hyperresponsive and when behavioral nociceptive thresholds were decreased to both mechanical and thermal stimuli, intrathecal infusions of the microglial inhibitor minocycline were initiated. Electrophysiological experiments showed that minocycline rapidly attenuated hyperresponsiveness of lumbar dorsal horn neurons. Behavioral data showed that minocycline restored nociceptive thresholds, at which time spinal microglial cells assumed a quiescent morphological phenotype. Levels of phosphorylated-p38 were decreased in SCI animals receiving minocycline. Cessation of delivery of minocycline resulted in an immediate return of pain-related phenomena. These results suggest an important role for activated microglia in the maintenance of chronic central below-level pain after SCI and support the newly emerging role of non-neuronal immune cells as a contributing factor in post-SCI pain.

Topics: Animals; Chronic Disease; Male; Microglia; Minocycline; Motor Activity; Pain; Rats; Rats, Sprague-Dawley; Spinal Cord Injuries; Thoracic Vertebrae

Minocycline, a clinically used tetracycline for over 40 years, crosses the blood-brain barrier and prevents caspase up-regulation. It reduces apoptosis in mouse models of Huntington's disease and familial amyotrophic lateral sclerosis (ALS) and is in clinical trial for sporadic ALS. Because apoptosis also occurs after brain and spinal cord (SCI) injury, its prevention may be useful in improving recovery. We analyzed minocycline's neuroprotective effects over 28 days following contusion SCI and found significant functional recovery compared to tetracycline. Histology, immunocytochemistry, and image analysis indicated statistically significant tissue sparing, reduced apoptosis and microgliosis, and less activated caspase-3 and substrate cleavage. Since our original report in abstract form, others have published both positive and negative effects of minocycline in various rodent models of SCI and with various routes of administration. We have since found decreased tumor necrosis factor-alpha, as well as caspase-3 mRNA expression, as possible mechanisms of action for minocycline's ameliorative action. These results support reports that modulating apoptosis, caspases, and microglia provide promising therapeutic targets for prevention and/or limiting the degree of functional loss after CNS trauma. Minocycline, and more potent chemically synthesized tetracyclines, may find a place in the therapeutic arsenal to promote recovery early after SCI in humans.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Caspase 3; Caspase Inhibitors; Caspases; Disease Models, Animal; Enzyme Activation; Female; Gliosis; Injections, Intraperitoneal; Minocycline; Nerve Degeneration; Neurons; Neuroprotective Agents; Protein Synthesis Inhibitors; Rats; Rats, Long-Evans; Rats, Sprague-Dawley; RNA, Messenger; Spinal Cord; Spinal Cord Injuries; Tetracycline; Treatment Outcome; Tumor Necrosis Factor-alpha

We investigated whether permeability transition-mediated release of mitochondrial cytochrome c is a potential therapeutic target for treating acute spinal cord injury (SCI). Based on previous reports, minocycline, a second-generation tetracycline, exerts neuroprotection partially by inhibiting mitochondrial cytochrome c release and reactive microgliosis. We first evaluated cytochrome c release at the injury epicenter after a T10 contusive SCI in rats. Cytochrome c release peaked at approximately 4-8 h postinjury. A dose-response study generated a safe pharmacological regimen that enabled i.p. minocycline to significantly lower cytosolic cytochrome c at the epicenter 4 h after SCI. In the long-term study, i.p. minocycline (90 mg/kg administered 1 h after SCI followed by 45 mg/kg administered every 12 h for 5 days) markedly enhanced long-term hind limb locomotion relative to that of controls. Coordinated motor function and hind limb reflex recoveries also were improved significantly. Histopathology suggested that minocycline treatment alleviated later-phase tissue loss, with significant sparing of white matter and ventral horn motoneurons at levels adjacent to the epicenter. Furthermore, glial fibrillary acidic protein and 2',3' cyclic nucleotide 3' phosphodiesterase immunocytochemistry showed an evident reduction in astrogliosis and enhanced survival of oligodendrocytes. Therefore, release of mitochondrial cytochrome c is an important secondary injury mechanism in SCI. Drugs with multifaceted effects in antagonizing this process and microgliosis may protect a proportion of spinal cord tissue that is clinically significant for functional recovery. Minocycline, with its proven clinical safety, capability to cross the blood-brain barrier, and demonstrated efficacy during a clinically relevant therapeutic window, may become an effective therapy for acute SCI.

Topics: Animals; Astrocytes; Body Weight; Cytochromes c; Disease Models, Animal; Female; Kinetics; Minocycline; Mitochondria; Oligodendroglia; Rats; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries

Minocycline has been demonstrated to be neuroprotective after spinal cord injury (SCI). However, the cellular consequences of minocycline treatment on the secondary injury response are poorly understood. We examined the ability of minocycline to reduce oligodendrocyte apoptosis, microglial/macrophage activation, corticospinal tract (CST) dieback, and lesion size and to improve functional outcome after SCI. Adult rats were subjected to a C7-C8 dorsal column transection, and the presence of apoptotic oligodendrocytes was assessed within the ascending sensory tract (AST) and descending CST in segments (3-7 mm) both proximal and distal to the injury site. Surprisingly, the numbers of dying oligodendrocytes in the proximal and distal segments were comparable, suggesting more than the lack of axon-cell body contiguity played a role in their demise. Minocycline or vehicle control was injected into the intraperitoneal cavity 30 min and 8 hr after SCI and thereafter twice daily for 2 d. We report a reduction of apoptotic oligodendrocytes and microglia within both proximal and distal segments of the AST after minocycline treatment, using immunostaining for active caspase-3 and Hoechst 33258 staining in combination with cell-specific markers. Activated microglial/macrophage density was reduced remote to the lesion as well as at the lesion site. Both CST dieback and lesion size were diminished after minocycline treatment. Footprint analysis revealed improved functional outcome after minocycline treatment. Thus, minocycline ameliorates multiple secondary events after SCI, rendering this clinically used drug an attractive candidate for SCI treatment trials.

Topics: Animals; Apoptosis; Axons; Caspase 3; Caspases; Disease Models, Animal; Microglia; Minocycline; Motor Activity; Neuroprotective Agents; Oligodendroglia; Rats; Rats, Wistar; Recovery of Function; Spinal Cord Injuries; Treatment Outcome

Injury in the peripheral or central nervous systems causes a significant rise in the levels of the pleiotropic cytokine leukemia inhibitory factor (LIF). This increase influences cell survival, reactive gliosis and inflammatory responses. Since prior work has focused primarily on peripheral nerve and brain, little is known about the role of LIF in the spinal cord injury response. We address this issue by examining the effects of injury in the LIF knockout (KO) mouse, as well as using an adenoviral vector to over-express LIF in the spinal cord of adult mice. We find that LIF over-expression results in a dramatic rise in cell proliferation, primarily in microglia/macrophages. Astrocytes are not stimulated to proliferate but are activated by the elevated LIF. LIF over-expression also causes the development of severe hindlimb motor dysfunction, an effect mediated by the enhanced activation of microglia/macrophages, as inhibiting microglial activation with minocycline attenuates these motor deficits. Conversely, proliferation is significantly diminished and the microglial/macrophage response to spinal cord injury is much less in the LIF KO compared to wild type (WT). Thus, LIF is a potent pro-inflammatory factor in the adult spinal cord and represents a potential target for the manipulation of inflammatory reactions after spinal cord injury.

Topics: Animals; Anti-Inflammatory Agents; Astrocytes; Cell Division; Disease Models, Animal; Female; Gene Transfer Techniques; Genetic Vectors; Hindlimb; Inflammation Mediators; Interleukin-6; Leukemia Inhibitory Factor; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia; Minocycline; Motor Activity; Spinal Cord; Spinal Cord Injuries; Up-Regulation

Acute spinal cord injury (SCI) produces tissue damage that continues to evolve days and weeks after the initial insult, with corresponding functional impairments. Reducing the extent of progressive tissue loss ('neuroprotection') following SCI should result in a better recovery from SCI, but treatment options have thus far been limited. In this study, we have tested the efficacy of minocycline in ameliorating damage following acute SCI in mice. This semi-synthetic tetracycline antibiotic has been reported to inhibit the expression and activity of several mediators of tissue injury, including inflammatory cytokines, free radicals and matrix metalloproteinases, making it a suitable candidate for study. Mice were subjected to extradural compression of the spinal cord using a modified aneurysm clip, following which they received treatment with either minocycline or vehicle beginning 1 h after injury. Behavioural testing of hindlimb function was initiated 3 days after injury using the Basso Beattie Bresnahan locomotor rating scale, and at 1 week using the inclined plane test. Functional assessments demonstrated that minocycline administration significantly improved both hindlimb function and strength from 3 to 28 days after injury compared with vehicle controls. Furthermore, gross lesion size in the spinal cord was significantly reduced by minocycline, and there was evidence of axonal sparing as determined using fluorogold labelling of the rubrospinal tract and by Bielchowsky silver stain. Finally, a comparison of minocycline against the currently approved treatment for acute SCI in humans, methylprednisolone, demonstrated superior behavioural recovery in the minocycline-treated animals.

Topics: Animals; Axons; Behavior, Animal; Hindlimb; Male; Mice; Minocycline; Neuroprotective Agents; Recovery of Function; Spinal Cord Injuries; Survival Rate

We examined the effects of minocycline, an anti-inflammatory drug, on functional recovery following spinal cord injury (SCI). Rats received a mild, weight-drop contusion injury to the spinal cord and were treated with the vehicle or minocycline at a dose of 90 mg/kg immediately after SCI and then twice at a dose of 45 mg/kg every 12 h. Injecting minocycline after SCI improved hind limb motor function as determined by the Basso-Beattie-Bresnahan (BBB) locomotor open field behavioral rating test. Twenty four to 38 days after SCI, BBB scores were significantly higher in minocycline-treated rats as compared with those in vehicle-treated rats. Morphological analysis showed that lesion size increased progressively in both vehicle-treated and minocycline-treated spinal cords. However, in response to treatment with minocycline, the lesion size was significantly reduced at 21-38 days after SCI when compared to the vehicle control. Minocycline treatment significantly reduced the number of terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL)-positive cells 24 h after SCI as compared to that of the vehicle control. DNA gel electrophoresis also revealed a marked decrease in DNA laddering in response to treatment with minocycline. In addition, minocycline treatment significantly reduced the specific caspase-3 activity after SCI as compared to that of vehicle control. Furthermore, RT-PCR analyses revealed that minocycline treatment increased expression of interleukin-10 mRNA but decreased tumor necrosis factor-alpha expression. These data suggest that, after SCI, minocycline treatment modulated expression of cytokines, attenuated cell death and the size of lesions, and improved functional recovery in the injured rat. This approach may provide a therapeutic intervention enabling us to reduce cell death and improve functional recovery after SCI.

Topics: Animals; Cell Death; Cytokines; Gene Expression Regulation; Male; Minocycline; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries

We describe an easy, minimal, rapid, and reproducible model of mouse spinal cord injury (SCI) that results in permanent paralysis involving one hind limb. We used this model to evaluate whether the paralysis can be prevented using two known neuroprotective drugs, namely leukemia inhibitory factor (LIF) and minocycline (MIN). Mice in the control vehicle (VEH) and MIN groups with SCI had negligible recovery of locomotor behavior. In contrast, the LIF groups showed a statistically significant improvement in locomotor behavior. Maximal recovery was observed when LIF was administered 2, 8, and 24 h after lesion, while no significant recovery was observed when LIF treatment commenced 1 week after the lesion. Unbiased stereological estimates revealed significantly higher numbers of myelinated axons below the lesion in the maximal recovery LIF groups. We conclude that LIF may be a useful treatment for recovery from paralysis after SCI.

Topics: Animals; Axons; Disease Models, Animal; Female; Interleukin-6; Leukemia Inhibitory Factor; Male; Mice; Minocycline; Motor Activity; Nerve Regeneration; Neuroprotective Agents; Paralysis; Recovery of Function; Spinal Cord Injuries; Time Factors