基于PI3K/Akt/Bad信号通路探讨益髓解毒方对血管性痴呆大鼠海马神经元凋亡的影响

Effect of Yisui Jiedu Prescription on Apoptosis of Hippocampal Neurons Based on PI3K/Akt/Bad Signal Pathway in Rats with Vascular Dementia

目的:探讨益髓解毒方对血管性痴呆(VD)大鼠海马神经元损伤及调控细胞凋亡信号通路磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(Akt)/淋巴细胞瘤-2(Bcl-2)关联死亡启动子重组蛋白(Bad)的作用机制。方法:40只SD大鼠分为假手术组、模型组、盐酸多奈哌齐组、益髓解毒方组,每组10只。双侧颈总动脉永久结扎(2-VO)法制备VD动物模型,假手术组和模型组灌胃生理盐水;盐酸多奈哌齐组灌胃盐酸多奈哌齐原药0.52 mg·kg-1;益髓解毒方组灌胃益髓解毒方颗粒(11.11 g·kg-1);1次/d。30 d后,以Morris水迷宫测试大鼠学习、记忆能力;苏木素-伊红(HE)染色观察海马CA1区组织形态结构;透射电镜(TEM)观察大鼠海马CA1区神经元超微结构;实时荧光定量聚合酶链式反应(Real-time PCR)检测Akt,Bad mRNA表达;蛋白免疫印迹法(Western blot)检测海马组织Akt,磷酸化(p)-Akt,Bad蛋白表达情况。结果:与假手术组比较,模型组大鼠学习、记忆能力下降明显(P<0.05),海马组织病理结构及神经元超微结构病变明显,海马组织Akt mRNA和Akt,p-Akt蛋白表达水平明显下降(P<0.05),Bad mRNA和Bad蛋白表达水平明显升高(P<0.05);与模型组比较,益髓解毒方组可明显提高大鼠的学习记忆能力,改善海马CA1区神经元细胞及超微结构变化,上调海马组织Akt mRNA和Akt,p-Akt蛋白表达水平,降低Bad mRNA和Bad蛋白表达水平(P<0.05)。结论:益髓解毒方可明显提高VD大鼠学习、记忆能力,改善海马组织及神经元超微结构病理变化,修复神经元受损细胞,这可能与促进Akt磷酸化,激活PI3K/Akt/Bad信号通路,发挥抗细胞凋亡保护神经元有关。

Objective:To investigate the effect of Yisui Jiedu prescription on hippocampal neuron damage in vascular dementia(VD)rats and to regulate phosphatidylinositol 3-kinase(PI3 K)/protein kinase B(Akt)/recombinant Bcl-2 associated death promoter(Bad)mechanisms of signaling pathways of neuronal apoptosis.Method:The 40 SD rats were divided into sham operation group,model group,donepezil hydrochloride group and Yisui Jiedu prescription group,with 10 rats in each group.VD animal model was prepared by bilateral carotid artery permanent ligation(2-VO)method.The sham operation group and the model group were intragastrically administered with normal saline,the donepezil hydrochloride group was intragastrically administered with donepezil hydrochloride 0.52 mg·kg-1.The Yisui Jiedu prescription group was administered with Yisui Jiedu prescription(11.11 g·kg-1),1 time/d.After 30 days,Morris water maze was used to test the learning and memory ability of rats,hematoxylin-eosin(HE)staining was used to observe the histomorphological structure of hippocampal CA1 region.Ultrasound of neuron in rat hippocampal CA1 region was observed by transmission electron microscopy(TEM).Real-time fluorescent quantitative(Real-time PCR)was used to detect the Akt,Bad mRNA expression.Western blot was used to detect the Akt,p-Akt and Bad protein expression in hippocampus.Result:Compared with sham operation group,the learning and memory ability of model group decreased significantly(P<0.05).The pathological structure and neuronal ultrastructure of the hippocampus were changed obviously.Hippocampal tissue Akt mRNA and the Akt,p-Akt protein expression level decreased significantly(P<0.05),and the levels of Bad mRNA and protein were significantly increased(P<0.05).Compared with model group,Yisui Jiedu prescription group can significantly improve the learning and memory ability of rats,improve the neuronal cells and ultrastructural changes in hippocampal CA1 area,and increase the expression of Akt mRNA and Akt,p-Akt protein in hippocampus.Decreased Bad mRNA and Bad protein expression levels(P<0.05).Conclusion:Yisui Jiedu prescription can significantly improve the learning and memory ability of VD rats,improve the ultrastructural pathological changes of hippocampus and neurons,and repair damaged neurons,which may promote Akt phosphorylation and activate PI3 K/Akt/Bad.The signaling pathway plays a role in the defense of neurons against apoptosis.