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AIM: To explored the potential role of HIF-1α in reducing the neuronal apoptosis and promoting the neuronal proliferation after stroke in rats. METHODS: The bone marrow-derived mesenchymal stem cells (BMSCs) were lentivirally transduced to express the stable form of HIF-1α. Ischemic stroke was induced by permanent middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. Neurological function was evaluated by modified neurological severity score (mNSS). Cerebral infarct volume was measured by TTC staining. Immunohistochemistry and terminal deoxynucleotidyltransferase mediated dUTP nick end labeling (TUNEL) method were performed to detect neuronal proliferation and apoptosis. RESULTS: Significant improvement of neurological deficits was found in BMSCs-mHIF-1α rats as compared to the control animals at 14th d and 28th d after MCAO (P<0.05). Significant reduction of infarct volume was observed in rats in BMSCs-mHIF-1α group at 3rd day after MCAO (P<0.05). Histological evaluation showed that BMSCs-mHIF-1α treatment significantly promoted neuronal survival and proliferation in the ischemic boundary area. CONCLUSION: Constitutive expression of HIF-1α in BMSCs reduces the neuronal apoptosis and promotes the neuronal proliferation after stroke in rats.
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[Objective] To investigate the effects of preconditioning with low concentration of hydrogen peroxide (H2O2) on oxidative stress-induced BMSC apoptosis.[Methods] In vitro separation,purification,culture,and amplification of bone marrow mesenchymal stem cells were performed.BMSC were insulted with 0,50,100,200,300,400,500 μmol/L H2O2 and the effect of different consentration of H2O2 on BMSC was detected by Flow cytometry (FCM).And then cells were preconditioned with different consentraion of H2O2.(FCM) was used to determine the protective role of H2O2 preconditioning on BMSC apoptosis,BMSC chromatin distribution changes were observed by Hoechst33324;BMSC Caspase-3 and Bcl-2 gene changes were detected by RT-PCR.[Results] Analysis of BMSC apoptosis by flow cytometry showed that H2O2 induced BMSC apoptosis in a dose-dependent manner,and pretreatment of the cells with low concentration of H2O2 prevented subsequent stimulation with high H2O2.RT-PCR results showed that preconditioning with low concentration of H2O2 reduced the BMSC Caspase-3 gene expression but increased Bcl-2 gene expression.[Conclusion] Preconditioning with low concentration of H2O2 has an adaptive role in BMSC,and its mechanism may be related to inhibit abnormal gene expression of Caspase-3 and increase the gene expression of Bcl-2.
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AIM:To explored the potential role of HIF-1? in reducing the neuronal apoptosis and promoting the neuronal proliferation after stroke in rats. METHODS:The bone marrow-derived mesenchymal stem cells (BMSCs) were lentivirally transduced to express the stable form of HIF-1?. Ischemic stroke was induced by permanent middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. Neurological function was evaluated by modified neurological severity score (mNSS). Cerebral infarct volume was measured by TTC staining. Immunohistochemistry and terminal deoxynucleotidyltransferase mediated dUTP nick end labeling (TUNEL) method were performed to detect neuronal proliferation and apoptosis. RESULTS:Significant improvement of neurological deficits was found in BMSCs-mHIF-1? rats as compared to the control animals at 14th d and 28th d after MCAO (P
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AIM:To investigate the role of SDF-1? in migrating of bone marrow stromal cells to the injured areas. METHODS:Ischemic brain lesion model was created in rats by permanent middle cerebral artery occlusion (MCAO). 48 SD rats were divided randomly into 2 groups. Group 1:phosphate buffered saline (PBS 1 mL) for control (n=25); Group 2:BMSCs (2?106) were injected intravenously at 24 h after MCAO (n=24). After propagated in BMSCs,Ad5/F35 GFP (green fluorescent protein) was infected to BMSCs. The expression of SDF-1? (stromal cell-derived factor-1?) mRNA in the penrumbral tissue was assayed by real-time quantitative PCR. The expression of CXCR4 on MSCs was detected by flow cytometry. Confocal microscopy was used to detect the GFP-labeled MSCs migration. RESULTS:Ad5/F35 GFP signals was observed in almost infected BMSCs. The expressions of SDF-1? mRNA in the thalamus and hippocampus of the ischemic brains were peaked at 3rd day after stroke,followed by a decrease at 14th day post-ischemia. The expression of SDF-1? mRNA in the cortex of the ischemic brains was peaked at 7th day post-ischemia,still at high level at 14th day post-ischemia. The median percentage of surface CXCR4 expression in BMSCs was 14%. GFP labeled BMSCs were detected in the origination of the middle cerebral artery (olfactory area) at 6 h,after 3 days in the prenumbra tissue such as thalamus,and in the cortex more labeled cells were found after 14 d post-ischemia.CONCLUSION:BMSCs can pass through the blood brain barrier of ischemic rats. Its mechanism might be associated with the expression of SDF-1? in the ischemic brain.