ERK信号通路抑制剂U0126对蛛网膜下腔出血大鼠早期脑损伤及神经元自噬的影响

The influence of U0126 of ERK signaling pathway inhibitor on early brain injury and neurons autophagy in SAH rats

目的探讨ERK信号通路特异性抑制剂U0126对蛛网膜下腔出血(SAH)对早期脑损伤及海马区神经细胞自噬的作用。方法成年雄性SD大鼠48只,随机数字表法分为对照组、SAH组、DMSO+SAH(二甲基亚砜)组、U0126+SAH组(ERK信号通路特异性抑制剂),共4组,每组各12只。采用血管内穿刺法(PIC)法制作SAH模型,分别于造模前30min经尾静脉注射等量的生理盐水、DMSO、U0126溶液0.5mL/只,于24h处死。干湿重法测量脑组织水含量,HE染色观察海马CA1区神经细胞形态结构变化;免疫组化及Western bloting检测海马区ERK及Beclin-1和LC3-Ⅱ表达水平的变化。结果与Sham组比较,SAH模型组脑组织含水量明显增加,大鼠海马CA1区神经元数量明显减少(P<0.05),ERK及自噬相关因子Beclin-1和LC3-Ⅱ的表达明显高于对照组(P<0.05);与SAH模型组比较,U0126组脑组织含水量明显增多,海马CA1区神经元数量明显较SAH组减少(P<0.05),ERK信号信号通路被抑制,相应自噬相关因子Beclin-1和LC3-Ⅱ的表达降低(P<0.05)。结论ERK信号通路抑制剂U0126可以抑制神经细胞自噬,加重SAH的早期脑损伤。

Objective To explore role of U0126, the specific inhibitor of ERK signaling pathway, in early brain injury （EBI） and the autophagy of nerve cells in hippocampus area in subarachnoid hemorrhage （SAH）. Methods A total of 48 male adult SD rats were randomly divided into control group, SAH group, DMSO-FSAH group, and U0126-FSAH group, with 12 in each. We established SAH rat model by the puncture of internal carotid artery. The same amount of saline water, DMSO and U0126 solution of 0.5 mL per rat was injected respectively into the rats of different groups 30 min before modeling. The rats were killed at 24 h. To measure brain water content by Wet and dry method after 24 h, the morphological changes of hippocampus CA1 neural cells were observed by microscopy; the expression levels of ERK, Beclin-1 and LC3 were detected by using immunohistochemical method. Results Compared with that in sham group, brain water content increased obviously in SAH model group. The density of surviving neurons in SAH group was significantly lower than that in control group （P〈 0.05）. ERK signaling pathway was activated obviously, the expressions of Beclin 1 and LC3-Ⅱ were significantly higher than those in control group （P〈0.05）. Compared with SAH model group, in U0126 group brain water content increased obviously. Compared with those in SAH group, the density of surviving neurons was significantly lower （P〈0.05）, ERK signaling pathway was suppressed, the expressions of Beclin-1 and LC3- Ⅱ were significantly lower （P〈0.05）. Conclusion The U0126, the ERK signaling pathway inhibitor, can inhibit neuron autophagy and increase EBR of SAH.