内质网应激在蛛网膜下腔出血后早期脑损伤中的作用机制

摘要

Objective To investigate whether autophagy activation participates in the neuroprotective effects of endo-plasmic reticulum (ER) stress- related neuroprotection in rat subarachnoid hemorrhage. Methods The rats were treated with ER stress inducer tunicamycin (Tm) or inhibitor tauroursodeoxycholic acid (TUDCA) intraperitoneal y, then subarachnoid hemor-rhage (SAH) was induced by endovascular perforation was performed in a total of 84 rats to induce. Autophagy inhibitor 3- methyladenine (3- MA) was administrated by intracerebral ventricular infusion to determine the relationship between autophagy and ER stress. Neurological evaluation was performed at 24 h after SAH, then al animals were sacrificed and their brain samples were col ected for molecular biology and histology studies. Results ER stress level was increased in rats after 24 h of SAH. Pre-treatment with Tm significantly improved neurological deficits, reduced the expression of caspase- 3 and the number of TUNEL- positive cel s. Pretreatment with TUDCA significantly aggravated neurological deficits and cel apoptosis. Western blot analysis revealed that levels of the autophagic protein Beclin 1 and the ratio of LC3- II to LC3- I were increased in Tm group and reduced in TUDCA group. Pretreatment with 3- MA blocked the Tm- induced anti- apoptotic effects. Conclusion Autophagy ac-tivation might contribute to ER stress- related neuroprotection in early brain injury fol owing SAH in rats.%目的探讨内质网应激（ERS）在蛛网膜下腔出血（SAH）后早期脑损伤中的作用机制。方法采用血管穿刺法制作大鼠SAH模型，应用ERS激动剂衣霉素（Tm）、抑制剂牛磺熊去氧胆酸（TUDCA）以及自噬抑制剂3-甲基腺嘌呤（3- MA）研究ERS与自噬在SAH后早期脑损伤中的作用。在SAH模型建立后24h对大鼠进行神经功能评估，留取脑组织后分别行分子生物学和免疫组织化学检测。结果 SAH后24h ERS水平显著激活，Tm预处理可显著改善SAH大鼠的神经功能，抑制促凋亡分子caspase-3的表达，减少TUNEL阳性细胞的数量。TUDCA则显著加重SAH大鼠神经功能障碍并导致神经细胞凋亡。Western blot结果显示，Tm预处理可显著降低自噬标记蛋白Beclin 1表达水平及LC3-Ⅱ/LC3-Ⅰ比值，而TUDCA具有相反的作用。通过侧脑室内给予3- MA则可显著抑制Tm介导的抗凋亡作用。结论 ERS对SAH后早期脑损伤具有神经保护作用，该作用与自噬的激活密切相关。