雌鼠母爱剥夺模型在应激反应中的特征

Maternal deprivation-induced stress responses in female rats

目的:探讨母爱剥夺对雌鼠成年后下丘脑-垂体-肾上腺(hypothalamo-pituitary-adrenal axis,HPA)轴活性和急性应激反应,以及下丘脑室旁核中性激素受体表达水平的影响。方法:建立雌性Sprague-Dawley大鼠母爱剥夺模型。成年后在其动情周期的不同阶段给予急性足底电击刺激。采用放射免疫法测定血浆中雌二醇和睾酮及促肾上腺皮质激素浓度,酶联免疫法测定血浆皮质酮浓度,免疫组织化学法检测下丘脑中雄激素和雌激素受体表达。结果:母爱剥夺后雌鼠血浆促肾上腺皮质激素和皮质酮水平在动情前期明显下降(P=0.012和P=0.019),下丘脑室旁核中雄激素受体在动情期表达下调(P=0.008)。结论:新生鼠母爱剥夺可以降低雌鼠HPA轴基础活性,该变化与外周性激素水平波动相关。SD雌性大鼠下丘脑内雄激素比雌激素对于CRH活性的调节作用更为显著。

Objective： To investigate the effect of maternal deprivation on the activity of hypothalamo-pituitary-adrenal（HPA） axis,acute stress response and the sex hormone receptors expression in hypothalamic paraventricular nucleus（PVN） in female rats.Methods： Maternal deprivation model was induced in female Sprague-Dawley（SD） rats.Foot shock was given at different stages of estrus cycle during the adulthood.Plasma estradiol,testosterone and adrenocorticotropin（ACTH） levels were determined by radioimmunoassay;and plasma corticosterone level was measured by enzyme linked immunosorbent assay.The expression of androgen receptor（AR） and estrogen receptor（ER-β） in the hypothalamic PVN was detected by immunohistochemistry.Results： Decreased plasma ACTH and corticosterone levels were found in the proestrus of female rats with maternal deprivation（P=0.012 and P=0.019,respectively）.A significant down-regulation（P=0.008） of PVN-AR,but not PVN-ER-β expression was found in female rats with maternal deprivation.Conclusion： Maternal deprivation may reduce the HPA axis activity in female SD rats,which is closely correlated with the fluctuation of the circulating sex hormones.The androgen in the hypothalamus seems to play a more important role than the estrogen in this procedure.