Wnt3a在大鼠蛛网膜下腔出血后早期脑损伤中对神经细胞自噬和凋亡的影响

目的 探讨Wnt3a在大鼠蛛网膜下腔出血(SAH)后早期脑损伤中对神经细胞自噬和凋亡的作用及影响。 方法 将75只健康雄性SD大鼠按随机数字表法分为假手术组(Sham组)、蛛网膜下腔出血组(SAH组)及干预组(Wnt3a组),每组25只;采用枕大池自体注血方法建立SAH模型,各组于出血后0、12、24、48、72 h取脑。Western bloting检测LC3Ⅱ与LC3Ⅰ的比值、Beclin-1、Caspase-3的表达情况,免疫组化染色技术观察各组大鼠海马的自噬和凋亡情况。 结果 Western bloting结果显示,SAH组LC3Ⅱ/Ⅰ、Beclin-1出血后呈升高趋势,于24 h达高峰,24 h时间点Wnt3a组LC3Ⅱ、Beclin-1的表达较SAH组明显(P<0.05)。SAH组出血后Caspase-3升高,48h达高峰,Wnt3a组Caspase-3表达较SAH组减少(P<0.05)。免疫组化结果显示,与SAH组相比,Wnt3a组24 h时间点Beclin-1阳性神经元增多,48 h时Bax阳性神经元与凋亡细胞均减少(P<0.05)。 结论 Wnt3a可以促进大鼠蛛网膜下腔出血后神经元自噬,减少神经元细胞凋亡,对神经元具有保护作用。

Effects of Wnt3a on neuronal autophagy and apoptosis in early brain injury after subarachnoid hemorrhage in rats

Objective To investigate the effects of Wnt3a on neuronal autophagy and apoptosis in early brain injury after subarachnoid hemorrhage(SAH)in rats. Methods A total of 75 SD male rats were randomly divided in to Sham group, SAH group and Wnt3a group. The SAH model was established by injecting autologous blood into cisterna magna. Brain was taken out after SAH at five different time points(0, 12, 24, 48, and 72 h). Western bloting was used to detect the ratio of LC3Ⅱ and LC3Ⅰ, and analyze the expressions of Beclin-1 and Caspase-3. An immunofluorescence technique was used to observe the autophagy and apoptosis of neurons. Results Western bloting results showed that in SAH group, expressions of LC3Ⅱ/Ⅰ and Beclin-1 increased after SAH and reached the peak at 24 h time point. The expressions of LC3Ⅱ and Beclin-1 in Wnt3a group were significantly higher than those in SAH group at 24 h time point(P<0.05). Caspase-3 expression, which in Wnt3a group was significantly lower than the SAH group(P<0.05), peaked at 48 h after SAH. Immunohistochemistry result showed that, compared with SAH group, the number of Beclin-1 positive neurons in Wnt3a group enhanced at 24 h while Bax positive neurons and apoptotic cells decreased at 48 h(P<0.05). Conclusion Wnt3a promotes neuronal autophagy and decreases neuronal apoptosis, which may protect the neurons.