Protectıve role of ıschemıc precondıtıonıng on rat testıcular ischemıa: effects of y-27632 and 5-hydroxydecanoıc acıd

Background/purpose: Torsion and detorsion of testis results in an ischemia/reperfusion (I/R) induced injury to the testis. Brief periods of ischemia with intermittent reperfusion protect an organ or tissue against a sustained period of subsequent ischemia. This phenomenon is known as ischemic preconditioning (IPC). This study was undertaken to determine the role of IPC on I/R-induced injury of rat testis. Furthermore, the effects of 5-hydroxydecanoic acid (5-HD), a selective KATP channel antagonist, and Y-27632, a selective Rho kinase inhibitor, on testis IPC was investigated.Methods: Ischemia was achieved by clamping of the testicular pedicle using a vessel clip. I/R injury was created by 180 min ischemia and 60 min reperfusion of the testis. One cycle IPC was created by 5 min trancient ischemia of the testis that was followed by 5 min reperfusion. Forty male adult Wistar albino rats were randomly allocated into 4 groups. Group 1 was served as untreated controls. The rats in Group 2 were subjected to I/R only. In group 3, 3 cycles of IPC performed prior to I/R. In groups 4 and 5, the rats were treated with intraperitoneal (i.p.) injection of 0.3 mg/kg Y-27632 and 10 mg/kg i.p. injection of 5-HD before 3 cycles of IPC that is followed by I/R. The rats were killed at the end of experimental protocols. Testis specimens were isolated for histopathology and biochemical investigation. Germinal epithelium was evaluated by the modified Johnson scoring (MJS) method. Biochemical analyses consisted of evaluation of tissue lipid peroxide (LOOH) levels, myeloperoxydase (MPO) activity, and total antioxidative capacity (TAC), total oxidative status (TOS) and oxidative stress index (OSI).Results: I/R lead to severe histopathological lesions in the rat testis such as vanishing of spermatozoa, spermatids and late spermatids, and significantly lowered the MJS when compared to unterated controls. I/R resulted in significant elevation in LOOH levels, MPO activity, and TAC, TOS and OSI levels. Protective effects of IPC on I/R induced testicular injury of rats were observed with the significant elevation in the testicular injury score, supression in MDA and MPO levels and increase in TAC, TOS and OSI. Y-27632 treatment only lead a significant decrease in MPO activity but there was no significant change in the remaining parameters when compared to group 3. 5-HD injection significantly depressed MJS and significantly increased all biochemical parameters, but TAC level, when compared to group 3.Conclusion: IPC protected rat testis against I/R-induced injury. As this effect is blocked by 5-HD, KATP channel appears to be a mediator of IPC in the rat testis. Y-27632 did not alter the effect of IPC in this experimental model.KEYWORDS: Ischemic preconditioning, testis, rat, Y-27632, 5-hydroxydecanoic acid