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目的探讨蜕皮甾酮(Ecdysterone,ECR)改善Aβ25-35诱导大鼠学习记忆功能障碍的作用机制。方法Wistar大鼠90只(♂)随机分为5组:对照组(control),模型组(Aβ),三个治疗组[ECR4mg.kg-1(Aβ+ECR4),ECR8mg.kg-1(Aβ+ECR8),Nimodipine7.2mg.kg-1(Aβ+-Ni7.2)],每组18只。大鼠双侧海马内注射Aβ25-35(每侧5μl,2μg.μl-1)诱导学习记忆功能障碍;水迷宫检测Aβ25-35诱导的大鼠学习记忆行为学改变;免疫组化SP法检测ChAT表达情况;AchE活性由试剂盒检测。结果①行为学的水迷宫检测结果显示,在连续4天的获得实验期间,与对照组比较,模型组找到平台的潜伏期和搜索距离明显增加(P<0.01);与模型组比较,高剂量ECR组及尼莫地平组大鼠找到平台的潜伏期和搜索距离相对缩短(ECR8mg.kg-1,P<0.01;-Ni7.2mg.kg-1,P<0.05)。在第5天撤去平台的记忆测试中:与对照组比较,模型组在原平台区的搜索时间及距离均缩短(P<0.01),而治疗组平台区的搜索时间及距离则相对增加(ECR4mg.kg-1P<0.05;ECR8mg.kg-1,P<0.01;Ni7.2mg.kg-1,P<0.05)。②胆碱乙酰转移酶(cholineacetyltransferase,ChAT)的分析结果显示,与对照组比较,模型组大鼠皮层及海马脑组织中的ChAT活性均明显降低(bothP<0.01);与模型组比较,高剂量ECR组及尼莫地平组大鼠皮层脑组织中ChAT活性均相对增加(ECR8mg.kg-1,P<0.01;Ni7.2mg.kg-1,P<0.05),而海马组织中只有高剂量ECR组的ChAT活性相对增加(ECR8mg.kg-1,P<0.05)。③胆碱脂酶(Acetylcholinesterase,AchE)的检测结果显示,各组大鼠的AchE活性无明显差别。结论ECR改善Aβ25-35大鼠学习记忆功能障碍,至少与皮层及海马脑组织中ChAT活性相对增加有关。
Objective To investigate the mechanism of ecdysterone (ECR) on improving learning and memory dysfunction induced by Aβ25-35 in rats. Methods 90 Wistar rats were randomly divided into 5 groups: control group, model group (Aβ), three treatment groups [ECR4mg.kg-1 (Aβ + ECR4) and ECR8mg.kg-1 + ECR8), Nimodipine 7.2 mg.kg-1 (Aβ + -Ni7.2)], 18 in each. Aβ25-35 (5μl, 2μg.μl-1 on each side) was injected into the hippocampus of rats to induce learning and memory dysfunction; water maze was used to detect the learning and memory behaviors of rats induced by Aβ25-35; immunohistochemical SP method was used to detect ChAT Expression; AchE activity detected by the kit. Results ① The behavioral water maze test showed that compared with the control group, the incubation period and the search distance of the model group were significantly increased (P <0.01), compared with the control group. Compared with the model group, the high dose ECR Compared with the nimodipine group, the latency to find the platform and the search distance were shortened (ECR8mg.kg-1, P <0.01; -Ni7.2mg.kg-1, P <0.05). In the memory test of removing the platform on day 5, the search time and distance of the model group in the original platform area were shortened (P <0.01) compared with the control group, while the search time and distance in the platform area of the treatment group were relatively increased (ECR4mg. kg-1 P <0.05; ECR 8 mg.kg-1, P <0.01; Ni 7.2 mg.kg-1, P <0.05). Choline acetyltransferase (ChAT) analysis showed that compared with the control group, the ChAT activity in the cortex and hippocampus of the model group was significantly decreased (both P <0.01). Compared with the model group, the high dose ChAT activity increased in ECR and nimodipine groups (ECR8mg.kg-1, P <0.01; Ni7.2mg.kg-1, P <0.05), while only hippocampal ECR Group ChAT activity increased (ECR8mg.kg-1, P <0.05). ③ Acetylcholinesterase (AchE) test results showed that there was no significant difference in AchE activity between groups. Conclusion ECR improves learning and memory dysfunction in Aβ25-35 rats, which is at least related to the relative increase of ChAT activity in cortex and hippocampus.