myelin-basic-protein and Reperfusion-Injury

Preclinical Research The aim of the present study was to evaluate the neuroprotective benefits of rhGLP-1 in diabetic rats subjected to acute cerebral ischemia/reperfusion injury induced by middle cerebral artery occlusion/reperfusion (MCAO/R). Streptozotocin (STZ)-induced diabetic rats were pretreated with rhGLP-1 (10, 20, or 40 μg/kg ip, tid) for 14 days. During this time, body weight and fasting blood glucose levels were assessed. Rats were then subjected to MCAO 90 min/R 24 h. At 2 and 24 h of reperfusion, rats were evaluated for neurological deficits and blood samples were collected to analyze markers of brain injury. Rats were then sacrificed to assess the infarction volume. rhGLP-1 pretreatment lowered blood glucose levels, improved neurological scores, attenuated infarct volumes, and reduced the blood levels of S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), and myelin basic protein (MBP). rhGLP-1 has neuroprotective benefits in diabetic rats with cerebral ischemia/reperfusion injury and could potentially be used as a prophylatic neuroprotectant in diabetic patients at high risk of ischemic stroke. Drug Dev Res 77 : 124-133, 2016.   © 2016 Wiley Periodicals, Inc.

Topics: Animals; Body Weight; Brain Ischemia; Diabetes Mellitus, Experimental; Disease Models, Animal; Glucagon-Like Peptide 1; Hypoglycemic Agents; Male; Myelin Basic Protein; Neuroprotective Agents; Phosphopyruvate Hydratase; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Reperfusion Injury; S100 Calcium Binding Protein beta Subunit; Streptozocin; Treatment Outcome

Oligodendrocytes play a crucial role in creating the myelin sheath that is an important component in neural transmission. In an animal model of transient cerebral ischemia, application of oligodendrocyte progenitor cells (OPCs) has not yet been reported. In this study, the effects of F3.Olig2 transplantation on memory and cognitive dysfunction were investigated in the aged gerbil in which ischemic stroke was induced. To investigate the possible mechanisms underlying repair, changes in the expression of myelin basic protein (MBP), oligodendrocyte-specific protein (OSP), and brain-derived neurotrophic factor (BDNF) were examined. Experimental ischemic stroke was induced by occlusion of bilateral common carotid arteries in aged gerbils. Gerbils (n=31 per group) were randomly divided into three groups: (1) vehicle sham group, (2) vehicle ischemia group, and (3) F3.Olig2 ischemia group. After 1, 3, and 7 days of ischemiareperfusion (I-R), saline or F3.Olig2 cells (1106 cells in 100 l) were injected into the gerbils intravenously. The gerbils were sacrificed 10 days after I-R for identification of grafted F3.Olig2 cells, and 15 and 30 days after I-R for tissue analysis after conducting passive avoidance and novel object recognition test. Injected F3.Olig2 cells and MBP, OSP, and BDNF were detected by specific antibodies using immunohistochemistry and/or Western blots. Memory and cognition were significantly increased in the F3.Olig2 ischemia group compared with the vehicle ischemia group. In the F3.Olig2 ischemia group, the neurons were not protected from ischemic damage; however, MBP, OSP, and BDNF expressions were significantly increased. Our results show that injection of F3.Olig2 cells significantly improved impaired memory and cognition, which might be related to increased MBP expression via increasing OSP and BDNF expression in the aged gerbil hippocampus following transient cerebral ischemia.

Topics: Animals; Brain-Derived Neurotrophic Factor; Calcium-Binding Proteins; Cell Line; Claudins; Gerbillinae; Glial Fibrillary Acidic Protein; Hippocampus; Humans; Immunohistochemistry; Ischemic Attack, Transient; Male; Myelin Basic Protein; Nerve Tissue Proteins; Neural Stem Cells; Reperfusion Injury

This study evaluated the function of mouse optic nerves after transient retinal ischemia using in vitro electrophysiologic recordings of compound action potentials (CAPs) correlated with diffusion tensor imaging (DTI) injury markers with confirmation by immunohistochemistry-determined pathology.. Retinal ischemia was induced in 7- to 8-week-old female C57BL/6 mice by elevating intraocular pressure to 110 mm Hg for 60 minutes. At 3 and 7 days after retinal ischemia, optic nerves were removed for CAP measurements. The CAP amplitude was recorded using suction electrodes in isolated control and injured optic nerves followed by ex vivo DTI evaluation. After DTI, optic nerves were embedded in paraffin and cut for immunohistochemical analyses.. Consistent with previous in vivo DTI measurements, a 25% decrease in axial diffusivity with normal radial diffusivity was seen at 3 days after retinal ischemia, suggesting axonal injury without myelin damage. At 7 days, there was no additional change in axial diffusivity compared with that at 3 days, but radial diffusivity significantly increased by 50%, suggestive of significant myelin damage due to sustained axonal injury. The relative anisotropy (RA) progressively decreased after retinal ischemia when compared with that of the controls. The CAP amplitude in injured nerves also progressively decreased after retinal ischemia, which correlated with the reduced RA (r = 0.80).. This study suggests that CAP amplitude reflects both axonal and myelin integrity and RA is an optimal parameter for functional assessment compared with axial or radial diffusivity alone in murine optic nerves after retinal ischemia.

Topics: Action Potentials; Animals; Axons; Diffusion Tensor Imaging; Disease Models, Animal; Electrophysiology; Female; Mice; Mice, Inbred C57BL; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Optic Nerve Diseases; Reperfusion Injury; Retinal Diseases; Retinal Ganglion Cells

Melatonin demonstrates neuroprotective properties in adult models of cerebral ischemia, acting as a potent antioxidant and anti-inflammatory agent. We investigated the effect of melatonin in a 7-d-old rat model of ischemia-reperfusion, leading to both cortical infarct and injury in the underlying white matter observed using MRI and immunohistochemistry. Melatonin was given i.p. as either a single dose before ischemia or a double-dose regimen, combining one before ischemia and one 24 h after reperfusion. At 48 h after injury, neither a significant reduction in cortical infarct volume nor a variation in the number of TUNEL- and nitrotyrosine-positive cells within the ipsilateral lesion was observed in melatonin-treated animals compared with controls. However, a decrease in the density of tomato lectin-positive cells after melatonin treatment was found in the white matter underlying cortical lesion. Furthermore, we showed a marked increase in the myelin basic protein-immunoreactivity in the cingulum and in the density of mature oligodendrocytes (APC-immunoreactive) in both the ipsilateral cingulum and external capsule. These results suggest that melatonin is not able to reduce cortical infarct volume in a neonatal stroke model but strongly reduces inflammation and promotes subsequent myelination in the white matter.

Topics: Animals; Brain Infarction; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Infant, Newborn; Infant, Newborn, Diseases; Magnetic Resonance Imaging; Melatonin; Myelin Basic Protein; Myelin Sheath; Myelitis; Neuroprotective Agents; Oligodendroglia; Plant Lectins; Rats; Reperfusion Injury

The aim of this study was to characterize the serum antibody reactivities occurring after ocular ischemia reperfusion. The time course of serum antibody responses was examined.. Wistar rats were exposed to transient ocular ischemia by elevating intraocular pressure to 130 mm Hg for 60 minutes. Axonal damage was evaluated on optic-nerve sections 2 and 4 weeks later. Blood samples collected before and several times after ischemia were used for antibody detection via customized protein microarrays. Different tissue antigens, including heat shock proteins (HSPs) and crystallins, were selected based on previous identification of antibody reactivities in studies on ischemic events or ophthalmic diseases associated with ischemia. Antibody reactivity was compared using multivariate statistical techniques.. Significant axonal damage was observed 2 and 4 weeks after ocular ischemia (P < 0.05). Animals showed certain immunoreactivities against antigens even before ischemia, whereas many reactivities increased afterward. Significantly different responses were detected 2, 3, and 4 weeks after ischemia (P < 0.05). Antibody reactivity against actin, glial fibrillary acidic protein, HSP 27, vimentin, or spectrin continually increased.. Ischemia induced by acute intraocular pressure elevation led to complex changes in antibody reactivities in sera of treated animals. Upregulation of serum autoantibodies, especially against heat shock and structural proteins, progressively increased throughout the 4-week follow-up period, whereas others such as ubiquitin decreased. The upregulation of anti-HSP 27 antibodies might be an attempt to protect the tissue from ischemic damage.

Topics: Animals; Autoantibodies; Autoantigens; Axons; Eye Proteins; Glial Fibrillary Acidic Protein; HSP27 Heat-Shock Proteins; Immunoglobulin G; Intraocular Pressure; Male; Myelin Basic Protein; Myelin Proteins; Myelin-Associated Glycoprotein; Myelin-Oligodendrocyte Glycoprotein; Optic Nerve; Protein Array Analysis; Rats; Rats, Wistar; Reperfusion Injury; Retinal Diseases; Retinal Vessels; Spectrin; Up-Regulation

Postresuscitation cerebral hypothermia is consistently neuroprotective in experimental preparations; however, its effects on white matter injury are poorly understood. Using a model of reversible cerebral ischemia in unanesthetized near-term fetal sheep, we examined the effects of cerebral hypothermia (fetal extradural temperature reduced from 39.4 +/- 0.1 degrees C to between 30 and 33 degrees C), induced at different times after reperfusion and continued for 72 hours after ischemia, on injury in the parasagittal white matter 5 days after ischemia. Cooling started within 90 minutes of reperfusion was associated with a significant increase in bioactive oligodendrocytes in the intragyral white matter compared with sham cooling (41 +/- 20 vs 18 +/- 11 per field, P < 0.05), increased myelin basic protein density and reduced expression of activated caspase-3 (14 +/- 12 vs 91 +/- 51, P < 0.05). Reactive microglia were profoundly suppressed compared with sham cooling (4 +/- 6 vs 38 +/- 18 per field, P < 0.05) with no effect on numbers of astrocytes. When cooling was delayed until 5.5 hours after reperfusion there was no significant effect on loss of oligodendrocytes (24 +/- 12 per field). In conclusion, hypothermia can effectively protect white matter after ischemia, but only if initiated early after the insult. Protection was closely associated with reduced expression of both activated caspase-3 and of reactive microglia.

Topics: Animals; Caspase 3; Caspases; Cerebral Cortex; Demyelinating Diseases; Enzyme Activation; Female; Fetus; Hypothermia, Induced; Hypoxia-Ischemia, Brain; Immunohistochemistry; In Situ Hybridization; Microglia; Myelin Basic Protein; Myelin Proteolipid Protein; Oligodendroglia; Pregnancy; Proliferating Cell Nuclear Antigen; Reperfusion Injury; RNA, Messenger; Sheep; Time Factors

Insulin-like growth factor-1 (IGF-1) is known to be important for oligodendrocyte survival and myelination. In the current study, the authors examined the hypothesis that exogenous IGF-1 could reduce postischemic white matter injury. Bilateral brain injury was induced in near-term fetal sheep by 30 minutes of reversible carotid artery occlusion. Ninety minutes after ischemia, either vehicle (n = 8) or a single dose of 3 microg IGF-1 (n = 9) was infused intracerebroventricularly over 1 hour. White matter changes were assessed after 4 days recovery in the parasagittal intragyral white matter and underlying corona radiata. Proteolipid protein (PLP) mRNA staining was used to identify bioactive oligodendrocytes. Glial fibrillary acidic protein (GFAP) and isolectin B-4 immunoreactivity were used to label astrocytes and microglia, respectively. Myelin basic protein (MBP) density and the area of the intragyral white matter tracts were determined by image analysis. Insulin-like growth factor-1 treatment was associated with significantly reduced loss of oligodendrocytes in the intragyral white matter (P < 0.05), with improved MBP density (P < 0.05), reduced tissue swelling, and increased numbers of GFAP and isolectin B-4 positive cells compared with vehicle treatment. After ischemia there was a close association of PLP mRNA labeled cells with reactive astrocytes and macrophages/microglia. In conclusion, IGF-1 can prevent delayed, postischemic oligodendrocyte cell loss and associated demyelination.

Topics: Animals; Astrocytes; Brain; Fetal Diseases; Glial Fibrillary Acidic Protein; Insulin-Like Growth Factor I; Lectins; Microglia; Myelin Basic Protein; Myelin Proteolipid Protein; Oligodendroglia; Reperfusion Injury; RNA, Messenger; Sheep; Vasospasm, Intracranial