大豆异黄酮对肥胖大鼠弓状核及垂体α-MSH、POMC、Ob-Rb 表达的影响

Expression of α-MSH,POMC and Ob-Rb in the Arcuate Nucleus and Pituitary of Obese Rats Following Soybean Isoflavone Treatment

为了探究大豆异黄酮通过瘦素减重的作用机制,建立食源性肥胖大鼠模型,后进行低、中、高剂量(50,150,450 mg/kg)大豆异黄酮干预,并每周定期称量记录体重,采用苏丹Ⅲ染色、SABC免疫组织化学法和核酸原位杂交法,观察大豆异黄酮对肥胖大鼠体重、腹部脂肪细胞形态和下丘脑弓状核及垂体α-MSH、POMC mRNA、Ob-Rb mRNA表达的影响。结果显示,标准对照大鼠α-MSH在弓状核、垂体神经部和中间部均大量表达,POMC mRNA在弓状核和垂体仅少量表达,Ob-Rb mRNA仅在弓状核表达,同时肥胖大鼠3种因子表达均显著降低;大豆异黄酮干预后肥胖大鼠体重降低,腹部脂肪细胞面积缩小且形态分布明显改善,同时α-MSH、POMC mRNA、Ob-Rb mRNA表达增多。表明大豆异黄酮可能通过减少脂储、增加Ob-Rb表达从而促进具有抑食作用的POMC及其裂解物α-MSH产生,从而改善大鼠瘦素抵抗状态,发挥减重作用。

To study the weight loss mechanism of soy isoflavone dependent on leptin.In the present study,the food-induced obese rats model was established treated with low,medium and high dose soy isoflavone,to investigate the effects of soy isoflavone on body mass,morphology of fat cell inside the abdomen,expression of α-MSH、POMC mRNA、Ob-Rb mRNA in the hypothalamic arcuate nucleus and pituitary,by weighting every week,Sudan Ⅲ stai-ning,immunohistochemical and in situ hybridization analysis.The results showed α-MSH abundantly expressed in the arcuate nucleus,neurohypophysis and pars intermedia,POMC mRNA rarely expressed in the arcuate nucleus and pituitary,and Ob-Rb mRNA only expressed in the arcuate nucleus,simultaneously the three factors were signifi-cantly less present in fat rats.After treated with soybean isoflavones,the body weight of obese rats decreased,the ar-ea of abdominal fat cells reduced and distribution improved significantly,also the expression of α-MSH,POMC mR-NA,Ob-Rb mRNA increased,which could be positively correlated with the dose.Results suggested that soy isofla-vone might reduce fat storage and stimulated Ob-Rb expression,then promoted production of POMC and α-MSH, thus improve the state of leptin resistance in rats,and cause weight loss.