OBJECTIVETo investigate the effects of diet-induced obesity on the developmental process of testes in pubertal rats.

METHODSEighty 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.

RESULTSThe 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.

CONCLUSIONHigh-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.