Hei Changchun, Zhou Yujia, Zhang Chenyang, Gao Furong, Cao Meiling, Yuan Shilin, Qin Yixin, Li P Andy, Yang Xiao
Department of Human Anatomy, Histology and Embryology, Ningxia Medical University, Key Laboratory for Craniocerebral Diseases of Ningxia Hui Autonomous Region, Yinchuan, China.
Neuroscience Center, General Hospital of Ningxia Medical University, Yinchuan, China.
Metab Brain Dis. 2023 Feb;38(2):409-418. doi: 10.1007/s11011-022-01020-6. Epub 2022 Jun 7.
To investigate the effect of rapamycin on mitochondrial dynamic balance in diabetic rats subjected to cerebral ischemia-reperfusion injury. Male Sprague Dawley (SD) rats (n = 78) were treated with high fat diet combined with streptozotocin injection to construct diabetic model in rats. Transient middle cerebral artery occlusion (MCAO) of 2 hours was induced and the brains were harvested after 1 and 3 days of reperfusion. Rapamycin was injected intraperitoneally for 3 days prior to and immediately after operation, once a day. The neurological function was assessed, infarct volumes were measured and HE staining as well as immunohistochemistry were performed. The protein of hippocampus was extracted and Western blotting were performed to detect the levels of mTOR, mitochondrial dynamin related proteins (DRP1, p-DRP1, OPA1), SIRT3, and Nix/BNIP3L. Diabetic hyperglycemia worsened the neurological function performance (p < 0.01), enlarged infarct size (p < 0.01) and increased ischemic neuronal cell death (p < 0.01). The increased damage was associated with elevations of p-mTOR, p-S6, and p-DRP1; and suppressions of SIRT3 and Nix/BNIP3L. Rapamycin ameliorated diabetes-enhanced ischemic brain damage and reversed the biomarker alterations caused by diabetes. High glucose activated mTOR pathway and caused mitochondrial dynamics toward fission. The protective effect of rapamycin against diabetes-enhanced ischemic brain damage was associated with inhibiting mTOR pathway, redressing mitochondrial dynamic imbalance, and elevating SIRT3 and Nix/BNIP3L expression.
探讨雷帕霉素对糖尿病大鼠脑缺血再灌注损伤后线粒体动态平衡的影响。雄性Sprague Dawley（SD）大鼠（n = 78）采用高脂饮食联合链脲佐菌素注射处理以构建大鼠糖尿病模型。诱导2小时的短暂大脑中动脉闭塞（MCAO），再灌注1天和3天后取脑。雷帕霉素在手术前3天及手术后立即腹腔注射，每日1次。评估神经功能，测量梗死体积，并进行HE染色及免疫组化。提取海马蛋白并进行蛋白质印迹法检测mTOR、线粒体动力相关蛋白（DRP1、p-DRP1、OPA1）、SIRT3和Nix/BNIP3L的水平。糖尿病高血糖使神经功能表现恶化（p < 0.01），梗死面积增大（p < 0.01），缺血性神经元细胞死亡增加（p < 0.01）。损伤增加与p-mTOR、p-S6和p-DRP1升高以及SIRT3和Nix/BNIP3L受抑制有关。雷帕霉素改善了糖尿病加重的缺血性脑损伤，并逆转了糖尿病引起的生物标志物改变。高糖激活mTOR通路并导致线粒体动力学向裂变方向发展。雷帕霉素对糖尿病加重的缺血性脑损伤的保护作用与抑制mTOR通路、纠正线粒体动态失衡以及提高SIRT3和Nix/BNIP3L表达有关。
