The role of ghrelin on the morphometry and intracellular changes in the rat testis

Recent studies have implicated the peripheral actions of ghrelin in reproductive tissues. Expression of the functional ghrelin receptor, GHS-R1a, has been shown in Sertoli and Leydig cells as well as seminiferous tubules. Therefore, we investigated the effects of chronic administration of ghrelin on morphometry of testicular cells and its probable intracellular alterations. Thirty 45-day male Wistar rats were scheduled for the study and were divided into control and treatment groups. In the treatment group, 1nmol of ghrelin was administered as sc injection for 10 consecutive days or vehicle (physiological saline) to the control rats. Testes were taken by killing of rats on days 5, 15 and 40 after last injection and underwent for photomicrograph and electronmicrograph evaluations as well as stereological estimations. Testicular histomorphometry revealed a significant decrease in the different cell types except for spermatogonia in the treatment animals (P<0.01). Such a cellular decrease was also found in the stereological estimations in this group. Likewise, seminiferous tubules diameter and their germinal epithelium thickness decreased in the treated rats (P<0.01). In intracellular observations, much vacuolated mitochondria, limited endoplasmic reticulum, lesser intracellular organels and several detachment areas between cell membrane and its basement membrane were detected in the ghrelin-treated group. These findings indicate that ghrelin has anti-proliferative effects on different testicular cell types and is a negative modulator of male reproductive system.