食源性肥胖致不孕大鼠下丘脑弓状核内GnRH的表达下调

Down-regulation of the expression of gonadotropin-releasing hormone in hypothalamus arcuate nucleus in female rats of diet-induced obese infertility

目的探讨食源性肥胖致不孕大鼠中枢性激素表达变化以及对性腺轴的影响。方法将100只刚断乳雌性SD大鼠分2组。正常组20只,给予普通饲料。高能饲料组80只,饲高能饲料,根据Lee's指数及阴道涂片检查筛选出肥胖不孕大鼠22只,作为实验组。检测E2、T、leptin、FSH、LH的水平;观察卵巢的形态学变化以及促性腺激素释放激素在下丘脑弓状核的表达情况。结果实验组较正常组大鼠血清E2、T、leptin水平明显升高,FSH、LH水平明显降低;下丘脑弓状核GnRH表达明显减弱;实验组大鼠卵巢体积明显减小,卵巢中未见接近成熟的卵泡及黄体。结论肥胖导致大鼠的神经内分泌代谢紊乱,致使下丘脑-垂体-卵巢轴功能失调性无排卵而引起不孕。

Objective To investigate the expressions of central hormones in female rats of diet-induced obese infertility and its effect on hypothalamus-pituitary-gonadal axis. Methods 100 female and weaning SD rats were divided into two groups.The normal group with 20 rats were fed normal diet.According to Lee＇s index and vaginal smears,22 obese infertile rats were selected from the high-energy diet group with 80 rats,serving as experimental group. The levels of E2,T,leptin,FSH and LH in serum were evaluated.The morphological changes of ovarian and the expression of GnRH in arcuate nucleus of hypothalamus were observed. Results Compared with the normal group,serum E2,T and leptin levels were markedly elevated in experimental group, whereas FSH and LH were significantly decreased. The expression of GnRH in arcuate nucleus of hypothalamus was increased in experimental group.The volume of ovary decreased markedly and there are few nearly maturted follicle and corpus luteum in ovaries of experimental group. Conclusion The neuroendocrine metabolic disorder induced by obesity,led to the dysfunction of hypothalamic- pituitary-gonadal axis and caused anovulation, which might result in infertility.