损毁弓状核致大鼠肥胖型无排卵机制探讨

The Mechanism of Anovulation in Obesity Rats Infertility after the Arcuate Nucleus Lesion

目的:探讨注射谷氨酸钠损毁弓状核致大鼠肥胖后对其不孕的影响。方法:给新出生雌性Wistar大鼠皮下注射谷氨酸钠(实验组),连续5天,以损毁其弓状核建立肥胖模型。对照组注射等量0.9%氯化钠液,连续5天。最终筛选出实验组肥胖不孕大鼠模型20只和对照组大鼠20只。观察两组神经肽Y(NPY)、瘦素受体(leptinR)及促性腺激素释放激素(GnRH)在其下丘脑弓状核的表达变化;并测定血清雌二醇(E2)、睾酮(T)、瘦素(leptin)、卵泡刺激素(FSH)、黄体生成素(LH)的水平。结果:在实验组大鼠中,血清E2、T、leptin水平较对照组明显升高(P<0.05),FSH、LH水平较对照组明显降低(P<0.05);下丘脑弓状核NPY表达较对照组增强(P<0.05),而leptinR及GnRH免疫阳性胞体及纤维表达较对照组减弱(P<0.05)。结论:损毁弓状核致大鼠肥胖由于神经内分泌-代谢失调而引起GnRH水平降低,导致下丘脑-垂体-卵巢轴功能失调性无排卵而引起不孕。

Objective：To investigate the effects of obesity inducing infertility after the arcuate nucleus lesion by in- jection Glutamic Sodium in rats. Methods： Subcutaneous injection of Glutamic Sodium to 40 newborn female Wistar rats for 5 continuous days to create the obesity model by arcuate nucleus lesion, and another 40 rats were chosen as control. The expressions of neusopeptide Y （NPY）, leptin receptor, and gonadotrophin-releasing hormone （GnRH） in arcuate nucleus of hypothalamus were observed by immunohistochemistry, and the serum levels of estradial （F-2）, testosterone （T）, leptin, follicle stimulation hormone （FSH）, and luteotrophic hormone （LH） were measured by ra- dioimmunoassay （RIA）. Results： In 40 experimental rats, there were 80% rats in obesity status with energy imbal- ance by arcuate nucleus lesion.The serum E2, T, and leptin level in model group was significantly higher than that in control group （ P 〈 0.05）. And the level of FSH and LH was lower than that in control group （ P 〈 0.05）. The ex- pression of NPY in arcuate nucleus of hypothalamus in model group was significantly higher than that in control group （P〈0.05）, but the expression of leptin receptor and GnRH was less in model group than that in control group （ P 〈 0.05）.Conclusions： The arcuate nucleus lesion with Glutamic Sodium can cause the imbalance of neurcen- docrine metabolism by inducing the low-release of GnRH, and cause infertility due to anovulatory by disfunction of hypothalamus- pituatory- ovary axis.