不同时程应激对大鼠下丘脑弓状核和室周核神经细胞的影响

目的:观察不同时程应激对大鼠下丘脑弓状核和室周核神经细胞的影响及酪氨酸羟化酶(TH)的表达变化,为应激性损伤的机制研究提供病理形态学依据。方法:建立每日束缚固定8 h加冰水游泳5 min的应激大鼠模型,分为1、3、7、14、21d组及各时间点正常对照组,采用硫堇染色观察弓状核、室周核内神经细胞尼氏体变化及细胞形态学改变;TH免疫组织化学标记观察大鼠下丘脑弓状核和室周核内多巴胺能神经细胞阳性表达变化,采用全景组织细胞定量分析系统,进行统计分析。结果:较长时程反复的应激刺激导致了大鼠弓状核和室周核神经细胞细胞质内尼氏体消失及部分细胞固缩。TH免疫组织化学标记显示随着应激时程的延长,下丘脑弓状核和室周核内多巴胺能神经细胞阳性表达数目减少。结论:较长时程的反复应激刺激可导致大鼠下丘脑弓状核和室周核神经细胞损伤及多巴胺能神经细胞缺失。

Effect of different durations of stress on arcuate nucleus and periventricular nucleus in rat hypothalamus

Objective: To investigate the effects of different stress durations on neurons of arcuate nucleus(AN) and periventricular nucleus(Pe) in the hypothalamus as well as the changes of tyrosine hydroxylas(TH) positive cells,so as to provide morphological evidence for studying the mechanism of nerve injuries induced by stress.Methods: Models of stress rats were established by restraining the rats for 8 hours and giving them ice-water swimming for 5 minutes every day.The process lasted for 1,3,7,14 and 21 days,respectively.Thionine staining was used to display the morphological changes and Nissl body changes in AN and Pe.Immunohistochemistry and panoramic tissue quantitative analysis system were used to reveal the changes in the expression in TH protein.Results: Disappearance of Nissl body and pyknosis of neurons in AN and Pe were found in rats with a long period of repeated stress.Besides,with prolonged stress exposure,the number of TH positive cells in AN and Pe was significantly decreased.Conclusion: Long-term repeated stress could result in neuronal injury and the loss of dopaminergic neurons in AN and Pe of the hypothalamus.