营养性肥胖对青春期雄性大鼠睾丸发育过程的影响

Diet-induced Obesity Affects Testis Development in Pubertal Rats

目的:探讨以高脂饲料配方建立的营养性肥胖大鼠模型对青春期雄性大鼠睾丸发育过程的影响。方法:21日龄雄性清洁级SD大鼠80只,断奶适应性饲养3 d后,随机分为对照组(n=32)和实验组(n=48)。以高脂饲料建立营养性肥胖动物模型。观察喂养后第3、4、5、6周末(即鼠龄为6、7、8、9周)大鼠体重、Lee's指数、睾丸重量、附睾重量的变化;全自动生化分析仪检测外周血甘油三酯(TG)和总胆固醇(TC);全自动微粒子化学发光免疫分析系统检测血清T、E2;HE染色观察睾丸发育的形态学改变。结果:高脂喂养的实验组大鼠在第3周末平均体重已明显增加(P<0.05),至第6周末,实验组大鼠较对照组超重达26.6%(P<0.01),Lee's指数也明显大于对照组(P<0.01);实验组大鼠第5、6周末的睾丸系数下降明显(P<0.05);实验组每周龄大鼠血清TG,TC水平均比对照组明显升高;实验组每周龄大鼠的T水平均明显低于对照组(P<0.05),E2水平在第3、4、5周虽低于对照组,而在第6周则呈现明显增加趋势,且显著高于对照组(P<0.01);光镜下可见实验组大鼠睾丸生精上皮细胞排列紊乱,细胞层次减少,成熟的精子数量较少。结论:高脂、高能量饮食可诱发青春期雄性大鼠营养性肥胖,随着肥胖程度的逐渐加重,可造成睾丸发育不全、睾丸生殖内分泌功能障碍。

Objective： To investigate the effects of diet-induced obesity on the developmental process of testes in pubertal rats. Methods： Eighty 21-day-old male SD rats were randomly divided into a control group （n = 32 ） and an experiment group （n = 48 ） , and fed respectively on a normal diet and a high-fat diet. And changes in the body weight, Lee＇s index, testis weight and epididymis weight were measured at the end of the 3rd, 4th, 5th and 6th week after the treatment, that is, when the rats were 6, 7, 8 and 9 weeks old. The concentrations of testosterone and estradiol were determined by Access immunoassay system and the morphological alterations in testis development observed by HE staining. Results： The body weight of the high-fat group obviously increased at the end of the 3rd week （ P 〈 0.05 ）, 26.6% heavier than that of the control by the end of the 6th week （ P 〈 0.01 ）, and Lee＇s index was also obviously increased （P 〈0.01 ）. Compared with the controls, the testicular coefficient declined in the high-fat group at the end of the 5th and 6th week （ P 〈 0.05 ） , plasma TG and TC remarkably increased, the testosterone level obviously decreased （ P 〈 0.05 ） , estradiol concentration lowered at the end of the 3rd, 4th and 5th week but dramatically increased at the 9th, with significant difference between the two groups （P 〈0.01 ）. Microscope examination showed that spermatogenic epithelial cells were arranged in disorder, the spermatogenic cell layers reduced and the number of mature sperms reduced. Conclusion ： High-fat diet can induce nutritional obesity in pubertal rats, which in turn may lead to the underdevelopment of the testis and the abnormal level of gonadal hormones.