Department of Neurosurgery, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai 200040, China.
Brain Res. 2012 Oct 30;1482:81-90. doi: 10.1016/j.brainres.2012.09.009. Epub 2012 Sep 13.
Alpha-lipoic acid (ALA) is an endogenous short-chain fatty acid that has beneficial protective effects against various vascular diseases. In this study, we sought to determine whether ALA could induce pre- or post-treatment protective effects against simulated ischemia and reperfusion-induced cerebral endothelial cell (CEC) injury by activating the Akt/mTOR pathway. CECs are currently considered to be an important target for ischemia therapy. Mouse brain endothelial cells (bEnd.3) and primary cultures of CECs were subjected to 6h of oxygen glucose deprivation (OGD) followed by 4h of simulated reperfusion, either alone or together with ALA administration before (pre-treatment) or immediately after (post-treatment) OGD. We found that pre-treatment administration of ALA reduced the OGD and simulated reperfusion-induced lactate dehydrogenase (LDH) release in bEnd.3 cells in a dose-dependent manner and that 1mM ALA pre- and post-treatments provided protection in both bEnd.3 cells and primary cultures of CECs. However, rapamycin, an mTOR inhibitor, was able to thoroughly abolish the protective effects of ALA. Western blotting showed that the ALA pre- and post-treatments up-regulated the phosphorylation of Akt, mTOR, S6K and 4E-BP1 in both bEnd.3 cells and primary cultures. However, after pre-treatment with rapamycin, the level of Akt phosphorylation was decreased in primary cultures of CECs but could still be restored by ALA, whereas the levels of mTOR, S6K and 4E-BP1 phosphorylation were significantly decreased and could not be restored. These results suggest that ALA pre- and post-treatments provide protective effects against simulated ischemia and reperfusion-induced CEC injury by promoting the Akt/mTOR pathway and that mTOR is required for ALA protection.
α-硫辛酸（ALA）是一种内源性短链脂肪酸，对各种血管疾病具有有益的保护作用。在这项研究中，我们试图确定 ALA 是否可以通过激活 Akt/mTOR 通路来诱导预处理或后处理对模拟缺血再灌注诱导的脑内皮细胞（CEC）损伤的保护作用。CEC 目前被认为是缺血治疗的一个重要靶点。用氧葡萄糖剥夺（OGD）处理小鼠脑内皮细胞（bEnd.3）和原代 CEC 培养物 6 小时，然后单独或与 OGD 后（后处理）或之前（预处理）给予 ALA 一起进行 4 小时的模拟再灌注。我们发现，ALA 的预处理剂量依赖性地降低了 bEnd.3 细胞中 OGD 和模拟再灌注诱导的乳酸脱氢酶（LDH）释放，并且 1mM ALA 的预处理和后处理均可在 bEnd.3 细胞和原代 CEC 培养物中提供保护。然而，mTOR 抑制剂 rapamycin 能够完全消除 ALA 的保护作用。Western blot 显示，ALA 的预处理和后处理均在上皮细胞 bEnd.3 和原代 CEC 培养物中上调了 Akt、mTOR、S6K 和 4E-BP1 的磷酸化。然而，在用 rapamycin 预处理后，原代 CEC 培养物中 Akt 磷酸化水平降低，但仍可被 ALA 恢复，而 mTOR、S6K 和 4E-BP1 磷酸化水平则显著降低且无法恢复。这些结果表明，ALA 的预处理和后处理通过促进 Akt/mTOR 通路提供对模拟缺血再灌注诱导的 CEC 损伤的保护作用，并且 mTOR 是 ALA 保护所必需的。
