Effects of streptozotocin-diabetes and insulin replacement on the epididymis of prepubertal rats: histological and histomorphometric studies.

The present study evaluates the effects of streptozotocin (STZ)-induced diabetes and insulin replacement on the histoarchitecture of caput, corpus, and caudal epididymides during the critical period of sexual maturation in rats. Prepubertal male Wistar rats (40 days old) were made diabetic by a single injection of STZ (120 mg/kg body weight, intraperitoneally). To one set of diabetic rats, insulin was replaced daily at a dose of 3 U/100g body weight, subcutaneously in two equally divided doses at 8:00 a.m. and 6:00 p.m. All the rats were killed on the 61st day of postnatal life. STZ-diabetes reduced the body weight and also caused regression of epididymis, leading to a decrease in the absolute weight of caput, corpus, and caudal regions. Histological studies also revealed a considerable reduction in the size of the tubule and lumen of these segments with an increase in interstitial stroma. Because of shrinkage of tubules, principal cells were packed tightly with clumping of nuclei. Stereological studies support atrophic changes in the caput, corpus, and caudal epididymides by reduction in tubular diameter, volume, and surface density. The epididymal lumen of STZ-treated rats was totally devoid of spermatozoa. These findings emphasize the detrimental effects of diabetes on the maintenance and establishment of fully differentiated epididymal epithelium during sexual maturation. Insulin replacement was only able to prevent the adverse effects of diabetes on certain parameters and this response was region-specific.