Department of Neurology, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China; Department of Neurology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.
Department of Neurology, Shanghai Sixth People's Hospital, Shanghai Jiao Tong University, Shanghai 200233, China.
Biochem Biophys Res Commun. 2014 Feb 7;444(2):182-8. doi: 10.1016/j.bbrc.2014.01.032. Epub 2014 Jan 16.
Rapamycin has been demonstrated to exhibit neuroprotective functions via the activation of autophagy in a cerebral ischemia model. However, the involvement of mitophagy in this process and its contribution to the protection of mitochondrial function remains unknown. The present study explored the characteristics of mitophagy after cerebral ischemia and the effect of rapamycin on mitochondrial function. Male Sprague-Dawley rats underwent transient middle cerebral artery occlusion (tMCAO). Neurological deficits scores; infarct volumes; mitophagy morphology; and the levels of malondialdehyde (MDA), adenosine triphosphate (ATP) and mitochondrial membrane potentials (Δψm) were examined. The expression of LC3, Beclin-1 and p62 in the mitochondrial fraction combined with transmission electronic microscopy were used to explore mitophagic activity after ischemia. We also blocked autophagosome formation using 3-methyladenine (3-MA) to check the linkage between the mitochondrial protective effect of rapamycin and enhanced mitophagy. We observed that rapamycin significantly enhanced mitophagy, as evidenced by the increase in LC3-II and Beclin-1 expression in the mitochondria and p62 translocation to the mitochondria. Rapamycin reduced infarct volume, improved neurological outcomes and inhibited mitochondrial dysfunction compared with the control animals (p<0.05). However, these protective effects were reversed by 3-methyladenine treatment after rapamycin. The present study indicates that rapamycin treatment attenuates mitochondrial dysfunction following cerebral ischemia, which is linked to enhanced mitophagy.
雷帕霉素通过在脑缺血模型中激活自噬来发挥神经保护作用。然而，在这个过程中，线粒体自噬的参与及其对线粒体功能保护的贡献尚不清楚。本研究探讨了脑缺血后线粒体自噬的特征，以及雷帕霉素对线粒体功能的影响。雄性 Sprague-Dawley 大鼠进行短暂性大脑中动脉闭塞（tMCAO）。检测神经功能缺损评分、梗死体积、线粒体自噬形态、丙二醛（MDA）、三磷酸腺苷（ATP）和线粒体膜电位（Δψm）水平。用 LC3、Beclin-1 和 p62 在线粒体部分的表达与透射电镜相结合，探讨缺血后自噬体的形成。我们还使用 3-甲基腺嘌呤（3-MA）阻断自噬体的形成，以检查雷帕霉素增强线粒体自噬与线粒体保护作用之间的联系。我们观察到雷帕霉素显著增强了线粒体自噬，表现为线粒体中 LC3-II 和 Beclin-1 的表达增加，以及 p62 向线粒体的易位。与对照组相比，雷帕霉素降低了梗死体积，改善了神经功能，并抑制了线粒体功能障碍（p<0.05）。然而，雷帕霉素处理后用 3-甲基腺嘌呤处理会逆转这些保护作用。本研究表明，雷帕霉素治疗可减轻脑缺血后线粒体功能障碍，这与增强的线粒体自噬有关。
