异钩藤碱对AD模型小鼠学习记忆及海马神经元凋亡的影响

Effects of isorhynchophylline on learning and memory and hippocampal neuron apoptosis in mice with Alzheimer’s disease

目的研究异钩藤碱(isorhynchophylline,IRN)对阿尔茨海默病(Alzheimer′s disease,AD)模型小鼠的学习记忆和海马神经元凋亡的影响。方法50只昆明小鼠雌雄各半,随机分为对照组、模型组、IRN低剂量组(20 mg·kg^(-1)·d^(-1))、IRN高剂量组(40 mg·kg^(-1)·d^(-1)),加兰他敏(galantamine,Gal)组(5.0 mg·kg^(-1)·d^(-1)),每组10只。D-半乳糖联合氯化铝构建AD小鼠模型。连续给药60 d后,采用Morris水迷宫测试认知能力,免疫组化染色法检测各组小鼠海马CA3区β-淀粉样蛋白1-42(β-amyloid protein 1-42,Aβ_(1-42))表达,Western Blot检测海马神经元Bcl-2、Bax、细胞色素c(cytochrome c,Cyt-c)、活化的半胱氨酸天冬氨酸蛋白酶-9(Cleaved caspase-9)和Cleaved caspase-3表达。结果与模型组小鼠比较,IRN各组小鼠Morris水迷宫逃避潜伏期缩短,目的象限停留时间延长,穿环次数增多(P<0.05);海马神经元Aβ_(1-42)、Bax、Cyt-c、Cleaved caspase-9和Cleaved caspase-3表达降低,Bcl-2表达升高(P<0.05)。结论IRN对AD模型小鼠的学习记忆具有一定的保护作用,其机制可能与降低Aβ_(1-42)水平以及抑制海马神经元凋亡有关。

Objective To investigate the effects of isorhynchophylline(IRN)on learning and memory in Alzheimer′s disease(AD)mice model,and hippocampal neuron apoptosis.Methods Fifty SPF-graded Kunming male and female mice were randomly divided into 5 groups,including control group,AD model group,low-dose IRN group,high-dose group and Gal group(10 mice in every group,including half male and half female).The AD mice model was established by D-galactose combined with aluminum chloride.After continuous administration for 60 days,mice were subjected to Morris water maze.The protein expressions of Aβ_(1-42)in the hippocampal CA3 areas were stained by immunohistochemistry.And the hippocampal protein expressions of Bcl-2,Bax,Cyt-c,Cleaved caspase-9 and Cleaved caspase-3 were detected by Western Blot.Results Comparing with AD model group,IRN groups mice shortened the latent period,spent more time in the target quadrant,and increased the entries times of target quadrant(P<0.05);in immunohistochemical staining with hippocampal CA3 areas,the protein expressions of Aβ_(1-42)were significantly attenuated in the IRN group(P<0.05);the expressions of Bax,Cyt-c,Cleaved caspase-9,Cleaved caspase-3 of IRN groups hippocampus were reduced,while the expressions of Bcl-2 were increased(P<0.05).Conclusion IRN can improve the learning and memory ability of AD mice,the mechanism may be related to reducing the expressions of Aβ_(1-42)in the hippocampus and inhibition of hippocampal neuron apoptosis.