tretinoin and Brain-Ischemia

Ischemic stroke is a neurological disease that causes brain damage by increasing oxidative stress and ion imbalance. Retinoic acid is a major metabolite of vitamin A and regulates oxidative stress, calcium homeostasis, and cell death. Intracellular calcium is involved in neuronal growth and synaptic plasticity. Parvalbumin is a calcium-binding protein that is mainly expressed in brain. In this study, we investigated whether retinoic acid has neuroprotective effects by controlling intracellular calcium concentration and parvalbumin expression in ischemic brain damage. Middle cerebral artery occlusion (MCAO) was performed to induce cerebral ischemia. Retinoic acid (5 mg/kg) or vehicle was injected into the abdominal cavity for four days before surgery and cerebral cortices were collected 24 h after MCAO for further studies. MCAO damage induced neurological deficits and histopathological changes and decreased parvalbumin expression. However, retinoic acid treatment alleviated these changes. In cultured neurons, glutamate (5 mM) exposure induced neuronal cell death, increased intracellular calcium concentration, and decreased parvalbumin expression. Retinoic acid treatment attenuated these changes against glutamate toxicity in a dose-dependent manner. It also regulates glutamate induced change in bcl-2 and bax expression. The mitigation effects of retinoic acid were greater under non-transfection conditions than under parvalbumin siRNA transfection conditions. Our findings showed that retinoic acid modulates intracellular calcium concentration and parvalbumin expression and prevents apoptosis in ischemic brain injury. In conclusion, retinoic acid contributes to the preservation of neurons from ischemic stroke by controlling parvalbumin expression and apoptosis-related proteins.

Topics: Animals; Apoptosis; Brain Ischemia; Calcium; Glutamic Acid; Infarction, Middle Cerebral Artery; Ischemic Stroke; Neurons; Neuroprotective Agents; Parvalbumins; Rats; Rats, Sprague-Dawley; Tretinoin

Ischemic stroke is a neurological disorder that causes pathological changes by increasing oxidative stress. Retinoic acid is one of the metabolites of vitamin A. It regulates oxidative stress and exerts neuroprotective effects. Thioredoxin is a small redox protein with antioxidant activity. The aim of this study was to investigate whether retinoic acid modulates the expression of thioredoxin in ischemic brain injury. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) surgery and retinoic acid (5 mg/kg) or vehicle was administered to adult male rats for four days prior to surgery. MCAO induced neurological deficits and increased oxidative stress and retinoic acid attenuated these changes. Retinoic acid ameliorated the MCAO-induced decrease in thioredoxin expression. MCAO decreases the interaction between thioredoxin and apoptosis signal-regulating kinase 1 (ASK1), and retinoic acid treatment alleviates this decrease. Glutamate (5 mM) exposure induced cell death and decreased thioredoxin expression in cultured neurons. Retinoic acid treatment attenuated these changes in a dose-dependent manner. Retinoic acid prevented the decrease of bcl-2 expression and the increase of bax expression caused by glutamate exposure. Moreover, retinoic acid attenuated the increases in caspase-3, cleaved caspase-3, and cytochrome c in glutamate-exposed neurons. However, the mitigation effects of retinoic acid were lower in thioredoxin siRNA-transfected neurons than in non-transfected neurons. These results demonstrate that retinoic acid regulates oxidative stress and thioredoxin expression, maintains the interaction between thioredoxin and ASK1, and modulates apoptosis-associated proteins. Taken together, these results suggest that retinoic acid has neuroprotective effects by regulating thioredoxin expression and modulating apoptotic pathway.

Topics: Animals; Apoptosis; Brain; Brain Ischemia; Caspase 3; Glutamic Acid; Infarction, Middle Cerebral Artery; Male; Neurons; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Thioredoxins; Tretinoin

Ischemic stroke is a severe neurodegenerative disease with a high mortality rate. Retinoic acid is a representative metabolite of vitamin A. It has many beneficial effects including anti-inflammatory, anti-apoptotic, and neuroprotective effects. The purpose of this study is to identify specific proteins that are regulated by retinoic acid in ischemic stroke. Middle cerebral artery occlusion (MCAO) was performed to induce focal cerebral ischemia. Retinoic acid (5 mg/kg) or vehicle was injected intraperitoneally into male rats for four days prior to MCAO operation. Neurobehavioral tests were performed 24 hr after MCAO and the cerebral cortex was collected for proteomic study. Retinoic acid alleviates neurobehavioral deficits and histopathological changes caused by MCAO. Furthermore, we identified various proteins that were altered by retinoic acid in MCAO damage. Among these identified proteins, adenosylhomocysteinase, isocitrate dehydrogenase [NAD

Topics: Animals; Brain Ischemia; Infarction, Middle Cerebral Artery; Ischemic Stroke; Male; Neurodegenerative Diseases; Neuroprotective Agents; Proteins; Proteomics; Rats; Rats, Sprague-Dawley; Rodent Diseases; Tretinoin

Oral alitretinoin is a retinoid used for severe chronic hand eczema. Although caution is recommended for patients with uncontrolled dyslipidaemia or cardiovascular risk factors, the actual atherothrombotic risk has not been investigated thus far.. To detect any excess of atherothrombotic events among patients exposed to alitretinoin, during treatment or in the 2 years following initiation.. Using the French Health Insurance database, we compared the number of patients who had an atherothrombotic event (coronary artery disease, ischaemic stroke or peripheral artery disease requiring revascularization) in the population exposed to oral alitretinoin vs. the general population of the same age, sex and baseline cardiovascular risk, using standardized morbidity ratios (SMRs).. Between 2009 and 2017, 19 513 patients were exposed to oral alitretinoin in France. Sixty-four (0·3%) patients had an atherothrombotic event while on alitretinoin. Patients receiving alitretinoin experienced no more atherothrombotic events than the general population: patients without cardiovascular risk factors or previous atherothrombotic events had a SMR of 0·65 [95% confidence interval (CI) 0·26-1·34] during alitretinoin treatment, and 1·21 (95% CI 0·90-1·59) in the 2 years following initiation; patients with cardiovascular risk factors or previous atherothrombotic events had a SMR of 0·82 (95% CI 0·60-1·08) during alitretinoin treatment and 0·95 (95% CI 0·82-1·09) in the 2 years following initiation. Taken separately, SMRs for each outcome did not increase either.. These data from an exhaustive nationwide population-based study do not support an increase in the incidence of atherothrombotic events with alitretinoin use, regardless of the baseline cardiovascular risk of the patient.

Topics: Alitretinoin; Brain Ischemia; Cohort Studies; Dermatologic Agents; Humans; Stroke; Tretinoin

Regulation of neural inflammation is considered as a vital therapeutic target in ischemic stroke. All-trans retinoic acid (atRA), a potent immune modulator, has raised interest in the field of stroke therapy. However, the immunological mechanisms for atRA-mediated neuroprotection remain elusive. The current study evaluated the impact of atRA on post-stroke neural inflammation and elucidated the mechanisms involved in the regulation of related neutrophil functions.. atRA was prophylactically administered to mice 1 day before transient middle cerebral artery occlusion (tMCAO, 1 h) and repeated daily immediately after reperfusion for 3 days. Stroke outcomes, neutrophil polarization, and formation of neutrophil extracellular traps (NETs) in the stroke lesion were assessed. Neutrophil depletion was induced with anti-Ly6G antibodies. Primary neutrophil cultures were used to explore the mechanisms of atRA treatment.. Prophylactic atRA treatment reduced infarct volumes and neurological deficits at 1 day after tMCAO. Post-stroke neural inflammation was attenuated and neutrophil accumulation in lesion was downregulated. atRA treatment skewed neutrophil toward N2 phenotype which facilitated its clearance by macrophage and inhibited NETs formation. The functions of neutrophil were indispensable in the protective effects of atRA and were associated with suppression to STAT1 signaling by atRA. Administration of atRA after stroke still provided efficient protection to cerebral ischemia.. atRA displays potent therapeutic efficacy in ischemic stroke by attenuating neural inflammation. Treatment of atRA impeded neutrophil accumulation, favored N2 polarization, and forbade NETs formation in ischemic lesion. STAT1 signaling played a decisive role in the mechanisms of atRA-afforded regulation to neutrophil.

Topics: Animals; Brain Ischemia; Cells, Cultured; Female; Male; Mice; Mice, Inbred C57BL; Neuroprotective Agents; Neutrophils; Signal Transduction; STAT1 Transcription Factor; Stroke; Tretinoin

Retinoic acid (RA), an active metabolite of vitamin A, possesses enormous protective effects on vascular systems. It may also be positively related to good functional outcome after ischemic stroke. However, whether circulating RA concentration is associated with poststroke cognitive impairment (PSCI) remains unclear. This study aimed to detect the association between RA level and PSCI among patients with first-ever acute ischemic stroke.. Two hundred and 61 consecutive patients were prospectively recruited during March 2018 and March 2019. Serum RA concentration was measured at admission for all patients. We also performed cognitive function examination using the Montreal Cognitive Assessment (MoCA) at admission and at every follow-up visit. Patients with MoCA score less than 26 were identified as developing PSCI.. The median serum RA level was 2.0 ng/mL (interquartile range, 1.1-3.2 ng/mL) after admission. Patients diagnosed as PSCI at admission, 1-month and 3-month were 53 (20.3%), 91 (34.6%), and 141 (54.0%), respectively. Univariate analysis showed that reduced RA level was correlated with PSCI at 3-month (P = .003), but not at admission (P = .416) and 1-month poststroke (P = .117). After adjusting for all potential confounders, the odds ratio for the lowest tertile of RA, compared with the highest tertile, was 1.97 (95% confidence interval, 1.01-3.83, P = .046) for PSCI at 3 months. Furthermore, multiple-adjusted spline regression model further confirmed the dose-response relationships between RA level and 3-month PSCI (P < .001).. Decreasing serum RA level might be associated with 3-month PSCI in ischemic stroke patients.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers; Brain Ischemia; Cognition; Cognitive Dysfunction; Female; Humans; Male; Middle Aged; Prognosis; Prospective Studies; Risk Assessment; Risk Factors; Stroke; Time Factors; Tretinoin

Previous studies suggest that retinoic acid (RA) can exert neuroprotective function in ischemic stroke. However, its role in post-stroke depression (PSD) has still been unclear. We sought to investigate the relationship between circulating RA levels and PSD in patients with ischemic stroke. From September 2018 to March 2019, we prospectively screened patients with ischemic stroke who were hospitalized within 7 days of symptoms onset. RA levels were measured after admission. All patients were followed up at 3 months after stroke. Diagnosis of PSD was made in line with the Chinese version of Structured Clinical Interview of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition criteria. PSD risk was estimated using multivariable regression models. In total, 352 ischemic stroke patients were enrolled for the final analysis. Up to 3 months after symptoms onset, 102 subjects experienced PSD. PSD patients showed significantly lower RA levels at baseline as compared to non-PSD patients. In univariate logistic analysis, reduced levels of RA was a significant predictor of PSD. These results were further confirmed in multivariate regression additionally controlled for possible relevant confounders. Our study shows that decreased serum RA levels at admission might be associated with 3-month PSD in ischemic stroke patients.

Topics: Aged; Brain Ischemia; Depression; Female; Humans; Male; Middle Aged; Prospective Studies; Stroke; Tretinoin

To explore the association between serum retinoic acid (RA) level in patients with acute ischemic stroke (AIS) and mortality risk in the 6 months after admission.. From January 2015 through December 2016, patients admitted to 3 stroke centers in China for first-ever AIS were screened. The primary endpoint was all-cause mortality or cardiovascular disease (CVD) mortality in the 6 months after admission. The significance of serum RA level, NIH Stroke Scale score, and established risk factors in predicting mortality were determined. The integrated discrimination improvement (IDI) and net reclassification improvement (NRI) statistics were applied in statistical analysis.. Of the 1,530 patients enrolled, 325 died within 6 months of admission, with an all-cause mortality of 21.2% and CVD-related mortality of 13.1%. In multivariable analysis, RA levels were expressed as quartiles with the clinical variables. The results of the second to fourth quartiles (Q2-Q4) were compared with the first quartile (Q1); RA levels showed prognostic significance, with decreased all-cause and CVD mortality of 55% and 63%, respectively. After RA was added to the existing risk factors, all-cause mortality could be better reclassified, in association with only the NRI statistic (. Low circulating levels of RA were associated with increased risk of all-cause and CVD mortality in a cohort of patients with first-incidence AIS, indicating that RA level could be a predictor independent of established conventional risk factors.

Topics: Aged; Aged, 80 and over; Brain Ischemia; Cause of Death; Cerebrovascular Disorders; China; Cohort Studies; Female; Follow-Up Studies; Humans; Incidence; Kaplan-Meier Estimate; Male; Middle Aged; Predictive Value of Tests; Risk Factors; Stroke; Survival Analysis; Treatment Outcome; Tretinoin

Perinatal stroke is often difficult to diagnose and an established treatment has not yet been validated, except for symptomatic measures. Herein, we propose to test the neuroprotective potential of the intravenous injection of retinoic acid-loaded nanoparticles (RA-NP) upon ischemic injury to the immature brain. The role of RA-NP on endothelial cells and organotypic slice cultures exposed to oxygen and glucose deprivation was assessed by evaluating markers pertaining to survival, proliferation, oxidative stress (NO, ROS), neuronal damage (enolase), vascular oxidation (p47phox) and microglia activation (CD68). Data showed that RA-NP (3 μg/ml) increased endothelial proliferation and survival, and normalized NO and ROS levels. The intravenous administration of RA-NP (10 μg/g) prevented ischemic injury in the hippocampus of 2-day-old mice by inhibiting cell death and normalizing markers of neurovascular function and inflammation. In sum, systemic administration of RA-NP protected neurovascular integrity and the inflammatory milieu from ischemia in the immature brain, highlighting its therapeutic value for perinatal stroke.

Topics: Administration, Intravenous; Brain; Brain Ischemia; Cells, Cultured; Human Umbilical Vein Endothelial Cells; Humans; Microglia; Nanoparticles; Neuroprotective Agents; Oxidative Stress; Tretinoin

All-trans retinoic acid (ATRA) influences the outcomes of cerebral ischemic reperfusion (CIR) injury, but the mechanism remains unclear. The present study aimed to investigate the effects of ATRA on loss of the blood brain barrier (BBB) following CIR and to explore the possible mechanisms. Transient middle cerebral artery occlusion was performed on male SD rats to construct an in vivo CIR model. Neurological deficits, BBB permeability, brain edema, MRI and JNK/P38 MAPK proteins were detected at 24 h following CIR. We demonstrated that ATRA pretreatment could alleviate CIR-induced neurological deficits, increase of BBB permeability, infarct volume, degradation of tight junction proteins, inhibit MMP-9 protein expression and activity. ATRA treatment also reduced the p-P38 and p-JNK protein level. However the protective effect of ATRA on CIR could be reversed by administration of retinoic acid alpha receptor antagonist Ro41-5253. SP600125 and SB203580, which is the JNK/P38 pathway inhibitors has the same protective effect as ATRA. These results indicated that ATRA may inhibit the JNK/P38 MAPK pathway to alleviate BBB disruption and improve CIR outcomes.

Topics: Animals; Blood-Brain Barrier; Brain Ischemia; Dose-Response Relationship, Drug; Male; MAP Kinase Signaling System; p38 Mitogen-Activated Protein Kinases; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Time Factors; Tretinoin

The aim of this study was to investigate whether exogenous retinoic acid (RA) can upregulate the mRNA and protein expression of growth-associated protein 43 (GAP-43), thereby promoting brain functional recovery in a rat distal middle cerebral artery occlusion (MCAO) model of ischemia. A total of 216 male Sprague Dawley rats weighing 300-320 g were divided into 3 groups: sham-operated group, MCAO+vehicle group and MCAO+RA group. Focal cortical infarction was induced with a distal MCAO model. The expression of GAP-43 mRNA and protein in the ipsilateral perifocal region was assessed using qPCR and immunocytochemistry at 1, 3, 7, 14, 21, and 28 days after distal MCAO. In addition, an intraperitoneal injection of RA was given 12 h before MCAO and continued every day until the animal was sacrificed. Following ischemia, the expression of GAP-43 first increased considerably and then decreased. Administration of RA reduced infarction volume, promoted neurological functional recovery and upregulated expression of GAP-43. Administration of RA can ameliorate neuronal damage and promote nerve regeneration by upregulating the expression of GAP-43 in the perifocal region after distal MCAO.

Topics: Animals; Brain Ischemia; GAP-43 Protein; Gene Expression; Immunohistochemistry; Infarction, Middle Cerebral Artery; Male; Neuroprotective Agents; Random Allocation; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Reproducibility of Results; Time Factors; Tretinoin; Up-Regulation

The purpose of this study was to observe the expression of LINGO-1 after cerebral ischemia, investigate the effects of retinoic acid (RA) on the expression of LINGO-1 and GAP-43, and the number of synapses, and to emplore the repressive effect of LINGO-1 on neural regeneration after cerebral ischemia. The model of permanent focal cerebral ischemia was established by the modified suture method of middle cerebral artery occlusion (MCAO) in Sprague-Dawley (SD) rats. The expression of LINGO-1 was detected by Western blotting and that of GAP-43 by immunohistochemistry. The number of synapses was observed by transmission electron microscopy. The SD rats were divided into three groups: sham operation (sham) group, cerebral ischemia (CI) group and RA treatment (RA) group. The results showed that the expression level of LINGO-1 at 7th day after MCAO in sham, CI and RA groups was 0.266 ± 0.019, 1.215 ± 0.063 and 0.702 ± 0.081, respectively (P<0.01). The number of Gap-43-positive nerve cells at 7th day after MCAO in sham, CI and RA group was 0, 59.08 ± 1.76 and 76.20 ± 3.12 per high power field, respectively (P<0.05). The number of synapses at 7th day after MCAO was 8.42 ± 0.13, 1.74 ± 0.37 and 5.39 ± 0.26 per μm², respectively (P<0.05). It is concluded that LINGO-1 expression is up-regulated after cerebral ischemia, and RA inhibits the expression of LINGO-1, promotes the expression of GAP-43 and increases the number of synapses. It suggests that LINGO-1 may be involved in the pathogenesis of cerebral ischemia, which may provide an experimenal basis for LINGO-1 antogonist, RA, for the treatment of cerebral ischemia.

Topics: Animals; Blotting, Western; Brain Ischemia; GAP-43 Protein; Gene Expression; Male; Membrane Proteins; Nerve Tissue Proteins; Neurons; Rats; Rats, Sprague-Dawley; Tretinoin

To investigate the cerebral infarct volume 24 hours after transient middle cerebral artery occlusion (tMCAO) and the proportion of CD4⁺;CD25⁺;Foxp3⁺; regulatory T cells (Tregs) in splenocytes in diverse periods after all-trans retinoic acid (ATRA) treatment in mice, so as to explore whether ATRA have the protection against cerebral ischemia damage in mice through intervening Treg differentiation.. Sixty male Kunming mice were randomly divided into two groups, i.e. pretreatment (n=40) and post-treatment (n=20) groups. Each group was against divided into two subgroups, i.e. tMCAO combined with ATRA treatment group, tMCAO combined with DMSO control group. Pretreatment groups: mice were treated intraperitoneally with ATRA (10 mg/kg) dissolved in 100 mL/L DMSO or equivalent volume of 100 mL/L DMSO daily for 7 days (n=20/group). Ten mice in each group were sacrificed and the proportion of Tregs in splenocytes was analyzed by flow cytometry (FCM) after 7-day pretreatment. The other 10 mice in each group were subjected to tMCAO by modified monofilament method. Neurologic deficit score (NDS) was recorded and the infarct volume was assessed by 2, 3, 5-triphenyltetrazolium chloride(TTC) staining 24 hours after tMCAO. The mice in post-treatment groups were treated intraperitoneally with ATRA (10 mg/kg) or equivalent volume of 100 mL/L DMSO immediately after the reperfusion of tMCAO modeling (n=10/group). NDS and infarct volume were assessed and the proportion of Tregs in splenocytes was analyzed 24 hours after tMCAO.. ATRA pretreatment for 7 days failed to improve neurologic function deficit (P>0.05) and to reduce the cerebral infarct volume (P>0.05) 24 hours after tMCAO in mice. ATRA post-treatment could markedly improve neurologic function (P<0.05) and reduce the cerebral infarct volume (P<0.05) 24 hours after tMCAO. However, neither ATRA pretreatment nor post-treatment had effect on the proportion of Tregs in the splenocytes of mice (P>0.05).. ATRA administered before tMCAO for 7 days failed to protect brain against ischemic damage. ATRA administered immediately following tMCAO induced cerebral protective effect 24 hours after tMCAO. The results suggest that Tregs change is not involved in the neuroprotection mechanism of ATRA.

Topics: Animals; Brain Ischemia; Cerebral Infarction; Flow Cytometry; Infarction, Middle Cerebral Artery; Male; Mice; Neuroprotective Agents; Random Allocation; Spleen; Stroke; T-Lymphocytes, Regulatory; Time Factors; Tretinoin

Retinoic acid (RA) plays an important role in the developing mammalian nervous system. Based on this concept, some studies have demonstrated the beneficial effects of RA administration on neurogenesis in neuropathological diseases. Some investigations have revealed the anti-inflammatory effects of RA treatment in multiple systems, in addition to its role in neurogenesis. To date, however, the neuroprotective efficacy of RA after cerebral ischemia, especially in the context of its anti-inflammatory effects, has been poorly demonstrated. Additionally, to the best of our knowledge, experiments of the therapeutic efficacy of RA treatment in a transient global ischemic model in the Mongolian gerbil have been lacking worldwide. Here, we studied the neuroprotective effects and neurobehavioral outcomes of intraperitoneally administered all-trans-RA (ATRA; a synthetic form of RA) on brains with transient global ischemia that was induced with the bilateral common carotid artery occlusion and reperfusion (BCCAO/R) model in the gerbil. In order to identify whether these neuroprotective mechanisms were due to the anti-inflammatory effects of ATRA, in vivo hippocampal expression of proinflammatory cytokines including tissue necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) after ATRA injection and in vitro levels of release of nitric oxide, TNF-α and IL-6 from lipopolysaccharide (LPS)-stimulated BV2 microglial cells after ATRA treatment were evaluated. The results showed that ATRA can protect pyramidal neurons in the hippocampal CA1 region against BCCAO-induced neuronal apoptosis and significantly reduce the extent of astrocytosis and microglial activation. In addition, the ischemia-induced neurobehavioral changes were normalized by ATRA injection. Consistent with these phenotypic data, we observed the diminishing effects of ATRA treatment on the production of proinflammatory mediators (e.g., TNF-α and IL-6) in hippocampal homogenates and LPS-stimulated BV2 cells, and these effects were dose-dependent. These results suggest a beneficial role of ATRA in the attenuation of global cerebral ischemia due to its anti-inflammatory properties, resulting in, at least partly, the inhibition of microglial secretion of variable proinflammatory cytokines.

Topics: Animals; Brain Ischemia; Cell Line; Encephalitis; Enzyme-Linked Immunosorbent Assay; Gerbillinae; Male; Neurons; Neuroprotective Agents; Tretinoin

Neurogenesis is regulated by a number of signaling pathways, including the retinoic acid (RA) pathway, a key regulator of neurogenesis in the subventricular zone (SVZ) and hippocampus. Acupuncture has been used to treat neurological conditions and is known to potentially enhance cell proliferation in the neurogenic area (hippocampal dentate gyrus and the SVZ of the lateral ventricle walls) in pathological conditions, which is associated with improved brain function. However, whether or not the neuroprotective effects of electroacupuncture (EA) are mediated by the regulation of the RA signaling pathway remains to be determined. Using a transient middle cerebral artery occlusion model, in the present study we evaluated the effect of EA on the neurological functional recovery, infarction volume and investigated the underlying molecular mechanisms. Two hundred and sixteen SD rats were randomly divided into 3 groups: sham, model group (ischemic rats without EA stimulation) and EA group (ischemic rats with EA stimulation on ST36 and LI11). Behavioral deficits were detected with high-resolution digital analysis of 24-h home-cage video recordings. Infarct volume was determined by triphenyltetrazolium hydrochloride staining and the expression of RA mRNA and protein was measured using RT-PCR and western blotting, respectively. We found that EA decreased the infarct volume, promoted neurological functional recovery and increased the RA mRNA and protein expression, compared with the model group. Findings of this study suggest that promoting neurological functional recovery by modulating RA expression in the post-ischemic brain is one of the mechanisms by which EA can be effective in the treatment of ischemic stroke.

Topics: Animals; Brain; Brain Ischemia; Cell Proliferation; Disease Models, Animal; Electroacupuncture; Hippocampus; Infarction, Middle Cerebral Artery; Lateral Ventricles; Male; Neurogenesis; Rats; Rats, Sprague-Dawley; Recovery of Function; Reperfusion Injury; Signal Transduction; Stroke; Tetrazolium Salts; Tretinoin

Retinoic acid (RA), a biologically active derivative of vitamin A, has protective effects against damage caused by H(2)O(2) or oxygen-glucose deprivation in mesangial and PC12 cells. In cultured human osteosarcoma cells, RA enhances the expression of bone morphogenetic protein-7 (BMP7), a trophic factor that reduces ischemia- or neurotoxin-mediated neurodegeneration in vivo. The purpose of this study is to examine whether RA reduces ischemic brain injury through a BMP7 mechanism. We found that intracerebroventricular administration of 9-cis-retinoic acid (9cRA) enhanced BMP7 mRNA expression, detected by RT-PCR, in rat cerebral cortex at 24 hr after injection. Rats were also subjected to transient focal ischemia induced by ligation of the middle cerebral artery (MCA) at 1 day after 9cRA injection. Pretreatment with 9cRA increased locomotor activity and attenuated neurological deficits 2 days after MCA ligation. 9cRA also reduced cerebral infarction and TUNEL labeling. These protective responses were antagonized by the BMP antagonist noggin given 1 day after 9cRA injection. Taken together, our data suggest that 9cRA has protective effects against ischemia-induced injury, and these effects involve BMPs.

Topics: Alitretinoin; Animals; Bone Morphogenetic Protein 7; Brain Ischemia; Carrier Proteins; Gene Expression; In Situ Nick-End Labeling; Infarction, Middle Cerebral Artery; Injections, Intraventricular; Male; Motor Activity; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Recovery of Function; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tretinoin

Ischemia-induced cerebral injury evolves over a longer period than previously believed through post-ischemic inflammation. Retinoic acid (RA) has been shown to exert cytoprotective effects on several cells, but its effects on ischemia-induced cerebral injury have been poorly characterized. The aim of the present study was to examine the effects of all-trans-RA on ischemia-induced cerebral injury and elucidate the underlying mechanism. All-trans-RA treatment reduced the size of the ischemia-induced cerebral infarct. To elucidate the underlying mechanism, ischemia-induced cerebral inflammation was studied by examination of expressions of interleukin 1beta (IL-1beta) and ED-1. RA treatment significantly reduced the cerebral inflammation. Moreover, cerebral ischemic induction of cyclooxygenase-2 (COX-2) and CCAAT/enhancer binding protein beta (C/EBPbeta), which binds to the COX-2 promoter, was also inhibited by RA. These results suggest that RA can reduce ischemia-induced cerebral injury by an anti-inflammatory action, which may be effected via inhibition of C/EBPbeta-mediated COX-2 induction.

Topics: Analysis of Variance; Animals; Anti-Inflammatory Agents; Blotting, Western; Brain; Brain Ischemia; CCAAT-Enhancer-Binding Protein-beta; Cyclooxygenase 2; Ectodysplasins; Immunohistochemistry; Interleukin-1beta; Male; Microscopy, Confocal; Neurons; Photomicrography; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; Tretinoin

Retinoic acid (RA) is an active metabolite of Vitamin A, and plays an important role in the normal development of the central nervous system. Neurogranin (NG) is a brain-specific postsynaptic kinase C (PKC) substrate and calmodulin-binding protein. The effects of RA-NG interaction on ischemic brain injuries are still unclear. We investigated the effects of exogenous RA on cerebral ischemia, the involvement of NG after distal middle cerebral artery occlusion (dMCAO), and the mechanism of RA neuroprotection in rats. Focal cortical infarction was developed in the dMCAO model, followed by intraperitoneal treatment with either vehicle or RA; then the rats were evaluated with neurological deficit scores according to a beam-walking test. The infarction volume was analyzed in hematoxylin and eosin (HE)-stained sections; NG mRNA expression level was measured with a real-time PCR; and NG protein expression was determined immunohistochemically at 3, 7, 14, 21 and 28 days after dMCAO. The RA-treated rats showed a significant improvement in functional deficits and a significant decrease in infarct volume after dMCAO, compared with the vehicle group. The RA group showed an increase in NG protein or mRNA expression, compared with the vehicle group. In conclusion, administration of RA decreased the infarct volume, and promoted neurological functional recovery. This neuroprotective effect is attributed, at least in part, to NG mRNA and NG protein expression.

Topics: Analysis of Variance; Animals; Behavior, Animal; Brain Infarction; Brain Ischemia; Disease Models, Animal; Gene Expression Regulation; Male; Neurogranin; Neuroprotective Agents; Psychomotor Performance; Rats; Rats, Sprague-Dawley; RNA, Messenger; Time Factors; Tretinoin

Neonatal stroke presents with seizures and results in neurologic morbidity, including epilepsy, hemiparesis, and cognitive deficits. Stem cell-based therapy offers a possible therapeutic strategy for neonatal stroke. We developed an immature mouse model of stroke with acute seizures and ischemic brain injury. Postnatal day 12 CD1 mice received right-sided carotid ligation. Two or 7 days after ligation, mice received an intrastriatal injection of B5 embryonic stem cell-derived neural stem cells. Four weeks after ligation, hemispheric brain atrophy was measured. Pups receiving stem cells 2 days after ligation had less severe hemispheric brain atrophy compared with either noninjected or vehicle-injected ligated controls. Transplanted cells survived, but 3 out of 10 pups injected with stem cells developed local tumors. No difference in hemispheric brain atrophy was seen in mice injected with stem cells 7 days after ligation. Neural stem cells have the potential to ameliorate ischemic injury in the immature brain, although tumor development is a serious concern.

Topics: Animals; Atrophy; Brain Ischemia; Brain Neoplasms; Carotid Arteries; Cell Survival; Ligation; Mice; Neurons; Seizures; Stem Cell Transplantation; Stem Cells; Stereotaxic Techniques; Stroke; Teratoma; Tretinoin

The induction of GRIM-19 has been shown to be essential for interferon-beta (IFN-beta)-induced and retinoic acid (RA)-induced tumor cell death. We have studied the localization and levels of GRIM-19 in IFN/RA-induced cell death in neural cells and in focal cerebral ischemia. Exposure to IFN/RA caused a approximately 15-fold increase in GRIM-19 protein levels and induced >50% cell death in human neuroblastoma SH-SY5Y cells. In rats subjected to permanent focal cerebral ischemia, increased oxidative stress, as well as increased GRIM mRNA levels (32-fold) and increased GRIM-19 (>50%) protein levels were noted in the ipsilateral (affected) hemisphere compared with the contralateral (unaffected) hemisphere. These results suggest that GRIM-19 may play a role in ischemia-induced neuronal cell death.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Brain Ischemia; Cell Line, Tumor; Drug Combinations; Gene Expression Regulation; Humans; Interferon-beta; Male; NADH, NADPH Oxidoreductases; Neuroblastoma; Rats; Rats, Wistar; Time Factors; Tretinoin

GFP labeled/NE-4C neural progenitor cells cloned from primary neuroectodermal cultures of p53- mouse embryos give rise to neurons when exposed to retinoic acid in vitro. To study their survival and differentiation in vivo, cells were transplanted into the cortex of 6-week-old rats, 1 week after the induction of a photochemical lesion or into noninjured cortex. The electrophysiological properties of GFP/NE-4C cells were studied in vitro (8-10 days after differentiation induction) and 4 weeks after transplantation using the whole-cell patch-clamp technique, and immunohistochemical analyses were carried out. After transplantation into a photochemical lesion, a large number of cells survived, some of which expressed the astrocytic marker GFAP. GFP/GFAP-positive cells, with an average resting membrane potential (Vrest) of -71.9 mV, displayed passive time- and voltage-independent K+ currents and, additionally, voltage-dependent A-type K+ currents (KA) and/or delayed outwardly rectifying K+ currents (KDR). Numerous GFP-positive cells expressed NeuN, betaIII-tubulin, or 68 kD neurofilaments. GFP/betaIII-tubulin-positive cells, with an average Vrest of -61.6 mV, were characterized by the expression of KA and KDR currents and tetrodotoxin-sensitive Na+ currents. GFP/NE-4C cells also gave rise to oligodendrocytes, based on the detection of oligodendrocyte-specific markers. Our results indicate that GFP/NE-4C neural progenitors transplanted into the site of a photochemical lesion give rise to neurons and astrocytes with membrane properties comparable to those transplanted into noninjured cortex. Therefore, GFP/NE-4C cells provide a suitable model for studying neuro- and gliogenesis in vivo. Further, our results suggest that embryonic neuroectodermal progenitor cells may hold considerable promise for the repair of ischemic brain lesions.

Topics: Animals; Antineoplastic Agents; Astrocytes; Brain Ischemia; Cell Differentiation; Cell Line; Cerebral Cortex; Denervation; Disease Models, Animal; Ectoderm; Graft Survival; Green Fluorescent Proteins; Immunohistochemistry; Membrane Potentials; Mice; Neurons; Oligodendroglia; Patch-Clamp Techniques; Photosensitizing Agents; Stem Cell Transplantation; Stem Cells; Tretinoin

p36 is a calcium/lipid-binding phosphoprotein that is expressed at high levels in proliferating and transformed cells, and at low levels in terminally differentiated cells, such as CNS neurons. The calcium-dependent binding to membrane phospholipids, and its capacity to interact with intermediate filament proteins suggest that p36 may be involved in the transduction of extracellular signals. The present work examines p36 gene expression in the mature CNS, primary primitive neuroectodermal tumors (PNETs), and transformed PNET cell lines. p36 immunoreactivity was not observed in normal adult human brain, but low levels of the protein were detected by Western blot analysis. Following acute anoxic cerebral injury, the mean levels of p36 protein were elevated two-fold, and injured neurons exhibited increased p36 immunoreactivity. This phenomenon was likely to have been mediated by post-transcriptional mechanisms since there was no corresponding change in the level p36 mRNA. p36 immunoreactivity was detected in 8 of 9 primary PNETs, and in 3 of 3 neurofilament-expressing PNET cell lines. The levels of p36 protein in PNET cell lines were 5-fold higher than in adult human brain tissue. Although p36 gene expression was generally high in proliferating PNET cells, the levels of p36 mRNA and protein were not strictly correlated with DNA synthesis. Instead, p36 gene expression was modulated in both proliferating and non-proliferating PNET cell cultures by treatment with 50 mIU/ml of insulin, 100 mM ethanol, or 5 microM retinoic acid. The frequent discordances observed experimentally and in vivo between p36 mRNA and p36 protein expression suggest that the steady-state levels of p36 protein in neuronal cells may be regulated primarily by post-transcriptional mechanisms.

Topics: Adult; Animals; Annexin A2; Astrocytoma; Brain; Brain Ischemia; Brain Neoplasms; Cell Differentiation; Ethanol; Gene Expression Regulation; Gene Expression Regulation, Neoplastic; Glioblastoma; Glioma; Humans; Hypoxia, Brain; Insulin; Membrane Lipids; Neoplasm Proteins; Nerve Tissue Proteins; Neurites; Neuroblastoma; Neuroectodermal Tumors, Primitive; Neurons; Rats; RNA, Messenger; RNA, Neoplasm; Transcription, Genetic; Tretinoin; Tumor Cells, Cultured