Ghrelin regulates bax and PCNA but not Bcl-2 expressions following scrotal hyperthermia in the rat

Background: We have reported the beneficial effects of ghrelin in improvement of histopathological features of the rat testis following local heat exposure. However, the exact mechanism of apoptosis- and proliferation-specific proteins in this regeneration process remained to be explored.Methods: Thirty adult male rats were allotted for the experiment and subdivided into three groups: control-saline (CS), heat-saline (HS) and heat-ghrelin (HG). The scrota of HS and HG groups were immersed in water bath at 43ºC for 15 min. HG animals received 2 nmol of ghrelin every other day until day 60 and saline to the other groups. The testes of all groups were taken after rat killing on days 30 and 60 after heat for immunocytochemical detection of pro-apoptotic factor Bax, anti-apoptotic protein Bcl-2 and proliferation-associated peptide PCNA in the germ cells.Result: Ghrelin could significantly suppress the bax expression in spermatocytes compared to the HS group on day 30. The mean percentages of spermatogonia containing bax substance were lower in ghrelin-exposed animals, however, the differences were not significant. There were immunoreactive cells against Bcl-2 in germ cell neither in the control nor in the heated animals. In contrast, the number of PCNA immunolabeling cells was higher in HG group compared to other animals. Down-regulation of bax expression concurrent with overexpression of PCNA in HG group indicates the ability of ghrelin in acceleration of testicular germ cells regeneration following heat stress.Conclusion: These findings indicate that ghrelin may be used as a novel antioxidant agent to induce resumption of spermatogenesis upon environmental heat exposure.Background: We have reported the beneficial effects of ghrelin in improvement of histopathological features of the rat testis following local heat exposure. However, the exact mechanism of apoptosis- and proliferation-specific proteins in this regeneration process remained to be explored.Methods: Thirty adult male rats were allotted for the experiment and subdivided into three groups: control-saline (CS), heat-saline (HS) and heat-ghrelin (HG). The scrota of HS and HG groups were immersed in water bath at 43ºC for 15 min. HG animals received 2 nmol of ghrelin every other day until day 60 and saline to the other groups. The testes of all groups were taken after rat killing on days 30 and 60 after heat for immunocytochemical detection of pro-apoptotic factor Bax, anti-apoptotic protein Bcl-2 and proliferation-associated peptide PCNA in the germ cells.Result: Ghrelin could significantly suppress the bax expression in spermatocytes compared to the HS group on day 30. The mean percentages of spermatogonia containing bax substance were lower in ghrelin-exposed animals, however, the differences were not significant. There were immunoreactive cells against Bcl-2 in germ cell neither in the control nor in the heated animals. In contrast, the number of PCNA immunolabeling cells was higher in HG group compared to other animals. Down-regulation of bax expression concurrent with overexpression of PCNA in HG group indicates the ability of ghrelin in acceleration of testicular germ cells regeneration following heat stress.Conclusion: These findings indicate that ghrelin may be used as a novel antioxidant agent to induce resumption of spermatogenesis upon environmental heat exposure.

کلیدواژه ها:

Bax ، Bcl-2 ، PCNA ، Testis ، Ghrelin