Pre-Ischemic Oxytocin Treatment Alleviated Neuronal Injury via Suppressing NF-κB, MMP-9, and Apoptosis Regulator Proteins in A Mice Model of Stroke.

Objective: This study was designed to determine the effects of pre-ischemic administration of oxytocin (OXT) on neuronal injury and possible molecular mechanisms in a mice model of stroke. Materials and Methods: In this experimental study, stroke was induced in the mice by middle cerebral artery occlusion (MCAO) for 60 minutes and 24 hours of reperfusion. OXT was given as intranasal daily for 7 consecutive days before ischemic stroke. Neuronal damage, spatial memory, and the expression levels of nuclear factor-kappa B (NF-κB), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), brain-derived neurotrophic factor (BDNF) and apoptosis were assessed 24 hours after stroke. Results: Pre-ischemic treatment with OXT significantly reduced the infarct size (P<0.01); but did not recover the neurological and spatial memory dysfunction (P>0.05). Moreover, OXT treatment considerably decreased the expressions of NF-κB, TNF-α, IL-1ß, and MMP-9 (P<0.001) and enhanced the level of BDNF protein. OXT treatment also significantly downregulated Bax expression and overexpressed Bcl-2 proteins. Conclusion: The finding of this study indicated that administration of OXT before ischemia could limit brain injury by inhibiting MMP-9 expression, apoptosis, inflammatory signaling pathways, and an increase in the BDNF protein level. We suggested that OXT may be potentially useful in the prevention and/or reducing the risk of the cerebral stroke attack, and could be offered as a new prevention option in the clinics.

Neuroprotective Effects of Chemerin on a Mouse Stroke Model: Behavioral and Molecular Dimensions.

The present study was conducted to investigate the effects of different doses of recombinant human Chemerin (rhChemerin) on brain damage, spatial memory, blood-brain barrier (BBB) disruption and cellular and molecular mechanisms in a mouse stroke model. The mouse stroke model was developed by blocking the middle cerebral artery for 1 h and performing reperfusion for 23 h. Immediately, one and three hours after the stroke, 200, 400 and 800 ng/mouse of intranasal rhChemerin was administered. Neuronal and BBB damage, spatial memory and neurological performance were examined 24 h after the stroke. Western blotting and immunofluorescence were utilized to determine the effects of rhChemerin on the expressions of nuclear factor kappa B (NF-κB), pro-inflammatory cytokines such as TNF-α and IL-1ß, anti-inflammatory cytokines such as IL-10 and TGF-ß and vascular endothelial growth factor (VEGF). Administering 400 and 800 ng/mouse of rhChemerin in the mice immediately and one hour after ischemia minimized the infarct size, BBB opening, spatial memory and neurological impairment (P < 0.001). Furthermore, 800 ng/mouse of rhChemerin significantly diminished terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive (apoptotic) cells, suppressed the expressions of NF-kB, TNF-α and IL-1ß and upregulated IL-10 and VEGF in the cortex and hippocampus of the mice. The present findings showed that rhChemerin administered immediately and one hour after stroke alleviates neuronal and BBB injures and improves spatial memory. These effects of rhChemerin may be mediated by inhibiting inflammatory pathways and apoptotic machinery.

Prophylactic effect of intranasal oxytocin on brain damage and neurological disorders in global cerebral ischemia in mice.

OBJECTIVES: A few experimental studies have shown the therapeutic effects of oxytocin on focal cerebral ischemia. In this study, the prophylactic effect of intranasal oxytocin on brain damage was investigated in a cerebral ischemic model. MATERIALS AND METHODS: Intranasal oxytocin (8 IU/per mouse) was prescribed daily for one week. Cerebral ischemia was performed through bilateral common carotid artery occlusion (BCCAO) for 20 min and then blood flow was restored for 24 hr. Finally, neurological disorders, spatial learning and memory, neuronal death, and neuronal apoptosis were assessed in CA1, CA3, and dentate gyrus. Also, levels of interleukin-1ß (IL-1ß) and Tumor necrosis factor-alpha (TNFα) were measured in the hippocampus. RESULTS: Induction of global ischemia leads to neurological disorders and impairment of spatial learning and memory that are improved by pre-treatment with oxytocin (P<0.01). Cresyl violet staining showed that pretreatment with oxytocin significantly reduced the number of dead nerve cells in CA1, CA3, and dentate gyrus by 40.7, 32, and 34.3%, respectively. Also, positive TUNEL cells in CA1, CA3, and dental gyrus decreased by 15, 30, and 27%, respectively. In addition, levels of TNFα and IL-1ß, which were extensively increased in ischemic mice, were significantly reduced with oxytocin pre-treatment. CONCLUSION: Pre-treatment of oxytocin reduces ischemic damage and improves neurological function and spatial memory. The neuroprotective effect of oxytocin is mediated by a decrease in cell death, apoptosis, and inflammatory mediators TNFα and IL-1ß. Pre-treatment with oxytocin may be useful in people who are prone to stroke.

Oxytocin Reduces Brain Injury and Maintains Blood-Brain Barrier Integrity After Ischemic Stroke in Mice.

The present study was designed to determine the effect of different doses of oxytocin (OXT) on neuronal injury, spatial memory, blood-brain barrier (BBB) integrity and to explore possible underlying molecular mechanisms in the early stage of stroke in mice. Stroke model was generated by middle cerebral artery occlusion (MCAO) for 60 min and 24 h reperfusion in mice. OXT at doses of 1, 2, 4 and 8 IU/per mouse was administrated intranasally at the beginning of brain ischemia. Brain injury, BBB integrity, and spatial memory were evaluated by standard methods. Changes in the expression of nuclear factor-kappa B (NF-κB), and TUNEL positive cell were detected by immunohistochemistry. The levels of vascular endothelial growth factor (VEGF), aquaporin-4 (AQP4) and brain-derived neurotrophic factor (BDNF) proteins were determined by western blotting and ELISA methods. OXT at doses of 4 and 8 IU/per mouse reduced the infarct size by 42% and 52%, respectively, and improved spatial memory function (p < 0.001). OXT (8 IU/per mouse) significantly reduced brain edema, BBB disruption and upregulated the AQP4 expression (p < 0.001). Finally, OXT significantly diminished the number of apoptotic, NF-κB positive cells and enhanced the expression of BDNF and VEGF proteins in the brain tissue (p < 0.001). These findings provide important evidences that OXT significantly suppresses neuronal damage in the early stage of stroke by inhibiting apoptotic and NF-κB signaling pathway, increasing the expression of VEGF, AQP4 and BDNF proteins and reducing the BBB leakage.

Probiotic supplementation attenuates hippocampus injury and spatial learning and memory impairments in a cerebral hypoperfusion mouse model.

Probiotics are referred to species of living microscopic organisms may help conserve the normal balance of the digestive system and/or manage diseases. A number of autoimmune, psychiatric, cardiovascular and cerebrovascular disorders may be associated with the imbalance of gut microbiota. This study examines the effect of 21 days consumption of multistrain probiotics on hippocampus injury, spatial and learning memory and some potential molecular mechanisms in a mouse model with cerebral hypoperfusion. Cerebral hypoperfusion was established in the mouse model by bilateral common carotid artery occlusion (BCCAO) for 20 min and 24 h reperfusion. Mixtures of several probiotic bacteria at concentrations of 107, 108 and 109 CFU/day were orally administrated for 3 weeks before the BCCAO. Spatial and learning memory, histological damage and apoptosis were assessed in the CA1, CA3 and dentate gyrus (DG) of the hippocampus 24 h after ischemia. The malondialdehyde (MDA) content and brain-derived neurotrophic factor (BDNF) level were measured by ELISA technique. Prophylactic of probiotic considerably reduced the number of apoptotic cells and neuronal death in the CA1, CA3 and DG of the hippocampus at all three concentrations (P < 0.001). In addition, probiotics reduced spatial memory impairment and neurological dysfunction only at the 109-CFU/day (P < 0.01). Nonetheless, probiotics did not change the levels of BDNF and MDA in the hippocampus (P > 0.05). According to the findings, the daily prophylactic ingestion of probiotics reduced hippocampus damage and prevented the spatial learning and memory deficit by suppressing apoptosis in the mouse model with cerebral hypoperfusion. Probiotic supplementation may be suggested as a useful preventive dietary strategy for groups susceptible to cerebrovascular diseases.