苜蓿总黄酮对未达性成熟期及成年雌性大鼠下丘脑-垂体-卵巢性腺轴相关基因表达量的影响

为研究苜蓿（Medicago sativa）黄酮对动物未达性成熟期及成年期下丘脑-垂体-卵巢性腺轴相关基因表达量的影响，以雌性大鼠为模式动物，分为5个试验组：3个苜蓿黄酮剂量组（120，400，1200 mg·kg^-1）和2个对照组（己烯雌酚0.5 mg·kg^-1、空白对照组）。结果表明：未达性成熟期雌鼠中、高剂量组和己烯雌酚组促性腺激素释放激素（GnRH）表达量显著降低（P<0.05）；低剂量苜蓿黄酮组促黄体生成素（LH）表达量显著高于高剂量组（P<0.05）；其卵巢中苜蓿黄酮高剂量组促卵泡生成素受体（FSHR）表达量极显著升高（P<0.01）；芳香化酶（CYP19A-1）在苜蓿黄酮低剂量组表达量极显著升高11倍（P<0.01），在己烯雌酚组显著升高8倍（P<0.05）。成年大鼠苜蓿黄酮3个剂量组和己烯雌酚组的GnRH表达量显著降低（P<0.05）；低剂量苜蓿黄酮的促黄体生成素受体（LHR）表达量极显著升高6倍（P<0.01），CYP19A-1表达量比空白对照提高8倍（P<0.05）。苜蓿黄酮对不同生理阶段雌鼠影响各不相同，但都通过下丘脑-垂体-卵巢性腺轴产生负反馈调节，并通过负反馈调节显著抑制了GnRH的表达，从而影响雌鼠性腺轴上其他相关基因的表达量。

Effects of Alfalfa Flavonoids on the Gene Expression of Hypothalamus-Pituitary- Ovarian Gonadal Axis in the Preadolescence and Maturity of Female Rat

The impacts of alfalfa flavonoids on the gene expression of hypothalamus-pituitary-ovarian gonadal axis in the preadolescence and maturity of animal were investigated. Three doses of alfalfa flavonoids (120, 400, 1200 mg·kg^-1) and two control groups (diethylstilbestrol 0.5 mg·kg^-1 control group) were designed in this experiment. Results showed that the expression of GnRH was significantly reduced by the middle and high doses of alfalfa flavonoids and diethylstilbestrol in the preadolescent of rat (P<0.05). The expression of LH was significantly increased by alfalfa flavonoids in low dose treatment compared with that in high dose treatment (P<0.05), whereas the expression of FSHR was significantly increased by alfalfa flavonoids in high dose treatment (P<0.01). The expression of CYP19A-1 was significantly increased 11 times by alfalfa flavonoids in low dose treatment (P<0.01), and was significantly increased 8 times by diethylstilbestrol (P<0.05). The expression of GnRH in hypothalamus was significantly reduced by alfalfa flavonoids and diethylstilbestrol in mature rat (P<0.05). The expression of LHR was significantly increased 6 times by alfalfa flavonoids in low doses group (P<0.01). The expression of CYP19A-1 was significant increased 8 times by alfalfa flavonoids in low doses group (P<0.05). Therefore, the impacts of alfalfa flavonoids had different effects on gene expression among the different developmental stages of rat. The expression of GnRH was significantly reduced by the negative feedback of hypothalamus-pituitary-ovarian gonadal axis, which then influenced other gene expressions.