大鼠海马内注射β-AP25-35后c-fos在脑内的变化及蜕皮甾酮的影响

目的观察大鼠海马内注射β-AP_25-35后学习记忆行为、c-fos基因表达变化及蜕皮甾酮的干预作用,以探讨蜕皮甾酮改善学习记忆的机制。方法大鼠双侧海马内微注射β-AP_25-35 10 μg,Morris water maze观察其学习记忆行为,免疫组化SABC法观察c-fos基因的表达。结果结果显示,与模型组比较,尼莫地平组及蜕皮甾酮(ECR)组的潜伏期缩短、搜索时间延长;同时模型组大鼠皮层及海马内c-fos蛋白表达明显降低,而高剂量ECR组c-fos蛋白的表达则相对增加。结论海马内注射β-AP_25-35可引起大鼠空间学习记忆障碍,并抑制c-fos的表达;ECR酮可改善β-AP引起的大鼠空间学习记忆障碍,并相对增加c-fos的表达。

Effect of ecdysterone on the expression of c-fos in the brain of rats induced by microinjection β-AP25-35 into the hippocampus

AIM: To observe the behavior in learning and memory and the expression of c-fos gene from the brain of rats induced by beta-AP25-35, and the intervention of ecdysterone, in order to explore the protective mechanism of ecdysterone on the dysfunction of learning and memory of the rat induced by beta-AP25-35. METHODS: Microinjection of beta-AP25-35 into hippocampus induced learning and memory dysfunction of rats. The learning and memory of rats were observed by Morris Water Maze. The expression of c-fos gene in the brain was detected by immunohistochemistry. RESULTS: The results of Morris Water Maze showed that after rats were microinjected beta-AP25-35 into hippocampus, the rats in model group took longer latency and searching distance compared with the ones in control group (P < 0.01), and the rats in treated group (ECR 4 mg x kg(-1), ECR 8 mg x kg(-1) and nimodipine 7.2 mg x kg(-1)) took shorter latency and searching distance, especially the ECR 8 mg kg(-1) group (P < 0.01). At the same time, after the 5 days training, there was a higher expression of c-fos in hippocampus and cortex from the rats in control group than that in model group (P < 0.01), but in the treated group, there was a relatively higher expression of c-fos, especially the ECR 8 mg x kg(-1) group (P < 0.01). CONCLUSION: Microinjection of beta-AP25-35 into the rat hippocampus resulted in dysfunction of learning and memory. Ecdysterone was shown to improve the learning and memory of the rats and increase the expression of c-fos. Increasing the expression of c-fos is probably one of the most molecular mechanism of its protection.