穹窿切断对大鼠下丘脑CRH表达的影响

目的观察穹窿切断对大鼠下丘脑促肾上腺皮质激素释放激素(CRH)表达的影响,探讨海马对HPA轴的抑制作用是否通过穹窿介导。方法成年健康雄性Wistar大鼠80只,随机分为穹窿切断组和假手术组,再分为0d、4d、7d、10d组,每组10只。建立大鼠穹窿切断模型,采用免疫组织化学和Westernblot技术检测穹窿切断组0d、4d、7d、10d时下丘脑CRH的表达变化和分布规律,并以假手术组相应时间段作为对照。结果穹窿切断组于7d时CRH表达升高,10d时升高显著。假手术组下丘脑仅有少量CRH表达。结论穹窿切断使CRH表达升高,HPA轴活动增强,海马对HPA轴的抑制作用减弱,揭示海马是通过穹窿纤维对HPA轴发挥抑制作用。

EFFECTS OF FORNIX TRANSECTION ON THE EXPRESSION OF CORTICOTROPIN-RELEASING HORMONE IN RAT HYPOTHALAMUS

Objective To observe the effects of fornix transection on the expression of corticotrophin-releasing hormone (CRH) in the hypothalamus of rats, amd to discuss whether the hippocampus plays a role in the tonic neuronal inhibition of the HPA axis via the fornix. Methods A total of 80 male Wistar rats were randomly divided into 4 fornix transection groups and 4 sham-operated groups with 10 rats each. The fornix transection model was established in the rats. The changes in the expression and concentration of CRH in the hypothalamus of rats were detected on 0d, 4d, 7d and 10d by immunohistochemistry and Western blot. The sham-operated groups showed as control groups. Results The expression of CRH increased on 7d and increased marheilly on 10d after fornux transection, but there was only a little expression of CRH in the hypothalamus of the sham-operated groups. Conclusion Fornix transection can increase the expression of CRH, enhance the activity of the HPA axis and decrease the inhibitory effects of the hippocampus on the HPA axis. This experiment reveals that it is via the fornix that the hippocampus plays a role in the tonic neuronal inhibition of the HPA axis.