The effects of chronic administration of ghrelin on rat sperm quality and membrane integrity

Abstract

Although ghrelin acts as a modulator of feeding behavior and energy metabolism in the central nervous system, recent studies have implicated the peripheral actions of ghrelin in reproductive tissues. Here, we investigated the eff ects of chronic administration of ghrelin on the motility, plasma membrane integrity and concentration of rat spermatozoa. 45-d male Wistar rats were scheduled for the study and were divided into control and treatment groups. In the treatment group, 1 nmol of ghrelin was administered as sc injection for 10 consecutive days or vehicle (physiological saline) to the control rats. Sperm collection was achieved by killing of the rats on days 15, 25 and 50 after fi rst injection. Total sperm motility and forward progressive movement did not exhibit signifi cant diff erence during the experiment, although, there was a tendency for greater motion rate on d 15 and 25 in the treated rats compared to the control group. Plasma membrane integrity (HOS-reacted spermatozoa) was signifi cantly higher in the treated animals, especially on day 15 as well as day 25, because of possible antioxidant properties of ghrelin. Th is value was statistically higher on day 15 than that of day 25 (P <0.05). Likewise, there was a signifi cant correlation between the FPM (P <0.0001, r = 0.79) and TSM (P <0.01, r = 0.52) with the HOS test percentage in the treatment group. It was not observed statistically diff erence in the sperm concentration between groups during all of the experimental days. In conclusion, chronic administration of ghrelin (similar to induced by energy defi ciency such as fasting) increased the integrity of sperm membrane, however, the sperm motility and concentration did not display any alterations.

Biochemical and histopathological evaluations of ghrelin effects following cadmium toxicity in the rat testis

“…Recently, antioxidant properties of ghrelin have been demonstrated in our laboratory in the rat testis (Kheradmand et al ., ) and ovary (Kheradmand et al ., ) so that ghrelin was able to promote antioxidant enzyme activities (especially GPx) and reduce lipid peroxidation in the testis. In addition, we indicated that chronic administration of ghrelin increases functional membrane integrity of rat spermatozoa (Kheradmand et al ., ). Likewise, the antioxidant properties of ghrelin are in consistent with our another study, in which we have shown that ghrelin enhances viability of rat spermatozoa during incubation at 37 °C up to 5 h, because of its antioxidant characteristics (Kheradmand et al ., ).…”

The effect of ghrelin pretreatment on epididymal sperm quality and tissue antioxidant enzyme activities after testicular ischemia/reperfusion in rats

“…Considering that epididymal spermatozoa are not protected by the microenvironment provided by the sertoli cell barrier, and plasma membrane of spermatozoa are rich in high level of polyunsaturated fatty acids [27], protection of spermatozoa against oxidative stress has a remarkable importance. It has been revealed that chronic injection of ghrelin (as a new antioxidant agent) significantly increases functional plasma membrane integrity in rat spermatozoa [13].…”

“…On the other hand, expression of GHS-R 1a in the seminiferous tubules strongly suggests that the seminiferous epithelium might be a target for ghrelin action and directly regulates seminiferous tubule functions [13]. Thus, it is expectable that injection of ghrelin may alter the number and/or proliferative rate of testicular cells.…”