脑梗死后室管膜下区ChAT^+神经元促进梗死周围区血管新生

Angiogenesis promotion in peri-infarction region by ChAT-positive neurons in subventricular zone after ischemic stroke

目的:观察脑梗死后室管膜下区(SVZ)胆碱乙酰基转移酶阳性(ChAT^+)神经元的活性变化及其对脑梗死周围区血管新生的影响,并探讨其可能的相关信号通路。方法:将小鼠随机分为假手术组、脑梗死组、阿托品组。采用电凝法夹闭大脑中动脉制备脑梗死模型。利用蛋白免疫印迹法测定各组ChAT/乙酰胆碱酯酶(AChE)、血管内皮生长因子(VEGF)、VEGF受体2(VEGFR2)及其下游分子磷酸化细胞外信号调节激酶(pERK)的表达情况,利用免疫荧光法观察表达VEGFR2和5-溴脱氧尿嘧啶(BrdU)/CD31的细胞数量变化。结果:脑梗术后14 d,脑梗死组SVZ区ChAT/AChE较假手术组高(P<0.05)。与假手术组相比,脑梗死组鼠的梗死周围区VEGF、VEGFR2、pERK表达量以及VEGFR2、BrdU/CD31阳性细胞数明显增多(P<0.05);与脑梗死组相比,阿托品组的上述指标含量减少(P<0.05)。结论:脑梗死后,SVZ区ChAT^+神经元活性相对增强,胆碱能系统效应增强,其可通过上调VEGF-VEGFR2信号通路促进脑梗死周围区的血管新生,促进脑功能恢复。

Objective To observe the activities of ChAT＋ neurons in subventricular zone （SVZ） after ischemic stroke and their effects on angiogenesis in peri-infarction region and related signaling pathways. Methods C57BL/6 mice were randomly assigned into sham group, middle cerebral artery occlusion （MCAO） group and atropine group. Isehemic models were made by permanent coagulation of the distal middle cerebral artery. The expression of CHAT, AChE in SVZ and VEGF, VEGFR2, pERK in peripheral regions of ischemic injury was evaluated by Western blotting and immunofluorescence. 5-bromodeoxyuridine （BrdU）/CD31 double-labeled cel｜s were also tested by immunofluorescenee. Results At 14 d after the surgery, the ratio of ChAT/AChE in SVZ increased after stroke （P 〈 0.05）. Compared with those in Sham group, the levels of VEGF, VEGFR2 and pERK were higher in MCAO group （P 〈 0.05） and VEGFR2-positive and BrdU/CD3 l-positive cells increased significantly. However, lower expression of VEGF, VEGFR2 and pERK and less VEGFR2-positive and BrdU/CD31-positive cells were found in atropine group when compared with that in MCAO group. Conclusions The activities of ChAT ＋ neurons in SVZ are enhanced after ischemic injury and they can promote angiogenesis in peripheral region of ischemic injury via upregulating VEGF-VEGFR2 signaling pathway and improving the brain function restoration.