Song Feifei, Guo Cen, Geng Yang, Wu Xuqing, Fan Wei
Department of Neurology, Zhongshan Hospital, Fudan University, 20032 Shanghai, China.
Department of Neurology, Zhongshan Hospital, Fudan University, 20032 Shanghai, China.
Brain Res. 2018 Jul 1;1690:12-22. doi: 10.1016/j.brainres.2018.04.005. Epub 2018 Apr 9.
Although recent studies have shown that mild hypothermia has neuroprotective effects on intracerebral hemorrhage (ICH), the therapeutic time window of the therapy and the role of autophagy as a potential neuroprotective mechanism remain unclear. This study was aimed to investigate the appropriate time window of mild hypothermia and the regulation of autophagy during the treatment in a rat model of autologous blood-injected ICH injury. The rats were divided into Sham, normothermic (NT) and hypothermic (HT) groups. HT groups received mild hypothermia (33 °C-35 °C) for 48 h starting from 3 h (HT3), 6 h (HT6), and 12 h (HT12) respectively after ICH. The neurological function, brain edema, blood brain barrier (BBB) permeability and volume of tissue loss were tested. The expression of metrix metalloproteinase 9 (MMP-9) and tight junction (TJ) protein including Occludin and Claudin-5 around the hematoma were detected by Western blot. Moreover, autophagy after ICH was detected by the ratio of LC3B-II/I, and the expression of Beclin-1 and p62, while apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dURP nick end labelling (TUNEL) staining and expression of Bcl-2, Bim, cleaved Caspase-3. Compared with NT group, neurological deficit, brain edema and BBB permeability were attenuated in HT6 and HT12 groups, but not in HT3 group, while volume of tissue loss was reduced only in HT12 group. The expression of MMP-9 and the degradation of Occludin and Claudin-5 were suppressed only in HT6 and HT12 groups, especially in the latter one. Moreover, neuronal autophagy and apoptosis induced by ICH were downregulated in HT12 group. The results suggested that mild hypothermia initiated at 6 h or 12 h post-injury was neuroprotective in ICH model of rats, especially at 12 h post-injury, via suppression of autophagy upregulated by ICH.
尽管最近的研究表明，轻度低温对脑出血（ICH）具有神经保护作用，但该疗法的治疗时间窗以及自噬作为一种潜在神经保护机制的作用仍不清楚。本研究旨在探讨在自体血液注射性ICH损伤大鼠模型中，轻度低温的合适时间窗以及治疗过程中自噬的调节情况。将大鼠分为假手术组、常温（NT）组和低温（HT）组。HT组分别在ICH后3小时（HT3）、6小时（HT6）和12小时（HT12）开始接受48小时的轻度低温（33°C - 35°C）治疗。检测神经功能、脑水肿、血脑屏障（BBB）通透性和组织损失体积。通过蛋白质免疫印迹法检测血肿周围基质金属蛋白酶9（MMP - 9）和紧密连接（TJ）蛋白（包括闭合蛋白和Claudin - 5）的表达。此外，通过LC3B - II/I的比率检测ICH后的自噬，以及Beclin - 1和p62的表达，同时通过末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）染色和Bcl - 2、Bim、裂解的半胱天冬酶 - 3的表达评估细胞凋亡。与NT组相比，HT6组和HT12组的神经功能缺损、脑水肿和BBB通透性有所减轻，但HT3组未减轻，而组织损失体积仅在HT12组减少。MMP - 9的表达以及闭合蛋白和Claudin - 5的降解仅在HT6组和HT12组受到抑制，尤其是后者。此外，HT12组中ICH诱导的神经元自噬和细胞凋亡下调。结果表明，在损伤后6小时或12小时开始的轻度低温对大鼠ICH模型具有神经保护作用，尤其是在损伤后12小时，其机制是通过抑制ICH上调的自噬。
