补阳还五汤促进脑缺血大鼠脑组织微结构重塑的作用

Effects of Buyang Huanwu Tang on promoting the microstructural remodeling of brain tissue in rats with cerebral ischemia

目的研究补阳还五汤改善脑缺血大鼠脑血流灌注、促进轴突生长及微结构重塑的药理作用及机制。方法线栓法制备右侧大脑中动脉栓塞脑缺血大鼠模型。将雄性SD大鼠随机分为假手术组、模型组和补阳还五汤组(16.1 g/kg),连续灌胃15 d后取材并检测指标。T2加权成像检测脑梗死体积;动脉自旋标记检测损伤脑区的血流灌注;弥散张量成像检测损伤脑区的超微结构。HE染色观察损伤脑区的病理损伤;免疫荧光染色法检测淀粉样前体蛋白(APP)、神经轴突生长抑制因子(NogoA)和神经轴突生长抑制因子受体(NgR)的蛋白表达,RT-PCR法检测生长相关蛋白-43(GAP-43)、NogoA和NgR的基因水平,以评价脑缺血大鼠轴突的生长及损伤情况。结果MRI结果显示,与模型组比较,补阳还五汤组大鼠的脑梗死体积减小(P<0.05),梗死核心及周围皮层的血流灌注增加(P<0.05),梗死灶周围皮层的超微结构改善。HE染色结果显示,补阳还五汤组大鼠较模型组皮层正常形态神经细胞数量增加,异常形态神经细胞数量减少(P<0.01或P<0.05),水肿程度减轻,神经纤维致密性提高。免疫荧光染色结果显示,补阳还五汤组大鼠较模型组梗死灶周围皮层及内囊APP、NogoA蛋白的阳性表达降低(P<0.05或P<0.01),内囊NgR蛋白阳性表达降低(P<0.05)。RT-PCR结果显示,补阳还五汤可下调梗死灶周围皮层NogoA、NgR基因表达水平(P<0.05或P<0.01)。结论补阳还五汤能够有效减小脑缺血大鼠的梗死体积,改善脑血流灌注和脑组织微结构,减轻神经细胞损伤,促进轴突生长及微结构重塑。

Objective To observe the pharmacological effects and mechanism of Buyang Huanwu Tang(Yang-Supplementing and Five-Returning Decoction,BYHWT)on improving cerebral perfusion,protecting nerve cells and promoting axon growth and microstructure remodeling in rats with cerebral ischemia.Methods Cerebral ischemia model was induced by right middle cerebral artery occlusion.Male SD rats were randomly divided into sham group,model group and BYHWT group.The BYHWT group received 16.1 g/kg of BYHWT by gavage while the other two groups received the same amount of normal saline for 15 consecutive days,after which tissues were taken and examined.T2-weighted imaging(T2 WI),arterial spin labeling(ASL)and diffusion tensor imaging(DTI)were applied to measure the infarct volume,analyze the changes in cerebral perfusion and detect the ultrastructure of the damaged brain region in cerebral ischemia rats respectively.Haematoxylin-eosin(HE)staining was used to observe the pathological damage of the injured brain region,immunofluorescence(IF)staining to detect expression levels of amyloid precursor protein(APP),NogoA and Nogo receptor(NgR),and real-time PCR(RT-RCR)to detect gene levels of NogoA and NgR and growth associated protein-43(GAP-43)in order to evaluate axon growth and injury in rats with cerebral ischemia.Results MRI results revealed the BYHWT group had decreased infarct volume,increased cerebral perfusion of the infarcted core and peripheral cortex,and improved ultrastructure of periinfarct cortex,compared with the model group(P<0.05).HE staining showed the number of normal cortical neurons was increased while the number of abnormal neurons was decreased(P<0.01 or P<0.05),the degree of edema was reduced,and the density of nerve fibers was increased in the BYHWT group.According to IF staining results,compared with the model group,BYHWT group showed reduced positive expression of APP and NogoA in infarcted peripheral cortex and internal capsule(P<0.05 or P<0.01),and decreased positive expression of NgR in internal capsule(P<0.05).RT-PCR results indicated that BYHWT reduced gene expression levels of NogoA and NgR in peripheral tissue of infarct in the cerebral ischemia rats(P<0.05 or P<0.01).Conclusion BYHWT can effectively reduce the infarct volume,improve cerebral perfusion and brain ultrastructure,reduce nerve cell injury,promote axon growth and microstructural remodeling in rats with cerebral ischemia.