PI3K-AKT信号通路在蛛网膜下腔出血后的抗凋亡作用

Protection of PI3K-AKT signaling pathway against neuronal apoptosis after subarachnoid hemorrhage in rats

目的蛛网膜下腔出血(subarachnoid hemorrhage,SAH)后病理生理机制复杂,其中神经元的凋亡及其影响逐渐被重视,实验探讨大鼠SAH后海马神经元的凋亡及PI3K-AKT信号通路的抗凋亡作用。方法建立大鼠枕大池2次注血模型,给药方法为枕大池注血前20 min经脑室注射,大鼠随机分为空白对照组、SAH模型组、SAH+去离子水处理组、SAH+DMSO(二甲基亚砜,有机溶剂)处理组、SAH+IGF-1(PI3K-AKT通路激动剂)处理组、SAH+Ly294002(PI3K-AKT通路抑制剂)处理组。分别于2次注血后1 d、3 d甲醛灌注取脑,通过免疫组化观察PI3K-AKT通路活化后P-AKT的表达,通过凋亡细胞原位末端标记技术(TUNEL)检测海马区神经元凋亡。结果 IGF-1激活PI3K-AKT通路后P-AKT表达增加可抑制神经元凋亡,而Ly294002阻断PI3K-AKT通路后P-AKT水平下降神经元凋亡明显增加。结论 PI3K-AKT通路激活后可明显减少SAH后神经元的凋亡,具有脑保护作用。

Objective The pathophysiology of subarachnoid hemorrhage（SAH） is rather complicated,in which neuronal apoptosis and its impact have been gradually highlighted.This experiment aimed at exploring the apoptosis of rat hippocampal neurons after SAH and the role of the PI3K-AKT signaling pathway in the protection of the neurons from apoptosis.Methods Rat SAH model was constructed by two-time blood injection in occipital cerebral fossa supplement.Sixty adult male Sprague-Dawley rats weighing 250-300 g were randomly divided into 6 groups： control,SAH,SAH＋H2O,SAH＋DMSO,SAH＋IGF-1,and SAH＋Ly294002.The rats were medicated 20 minutes before the blood injection.Perfusion-fixation was performed on the first and third day respectively after the second blood-injection for immunohistochemical detection of the P-AKT expression and for TUNEL determination of neuronal apoptosis in the hippocampus.Results The P-AKT expression in the hippocampal neurons was significantly higher（P0.05）,while the apoptosis rate of hippocampal neurons significantly lower（P0.01） in the SAH＋IGF-1 group than in the SAH＋Ly294002 and other groups.Conclusion The activation of the PI3K-AKT signaling pathway has an obvious neuroprotective effect by decreasing the apoptosis rate of hippocampal neurons after SAH in rats.