Melatonin attenuates ovarian ischemia reperfusion injury in rats by decreasing oxidative stress index and peroxynitrite.

BACKGROUND/AIM To evaluate the protective effect of melatonin on ovarian ischemia reperfusion injury in a rat model. MATERIALS AND METHODS Forty eight rats were separated equally into six groups; Group 1: sham, Group 2: surgical control with 3 hour bilateral ovarian torsion and detorsion, Group 3: intraperitoneal 5 % ethanol (1 mL) just after detorsion (as melatonin was dissolved in ethanol), Group 4: 10 mg/kg intraperitoneal melatonin 30 min before 3-hr torsion, Group 5; 10 mg/kg intraperitoneal melatonin just after detorsion, Group 6; 10 mg/kg intraperitoneal melatonin 30 min before torsion and just after detorsion. Both ovaries and blood samples were obtained 7 days after detorsion for histopathological and biochemical analysis. RESULTS In group 1, serum levels of total oxidant status (TOS) (?mol H2O2 equivalent/g wet tissue) were significantly lower than group 2 (p=0.0023) while tissue TOS levels were lower than group 3 (p=0.0030). Similarly, serum and tissue levels of peroxynitrite in group 6 were significantly lower when compared to group 2 (p=0.0023 and p=0.040, respectively). Moreover, serum oxidative stress index (OSI) (arbitrary unit) levels were significantly increased in group 2 when compared to groups 1 and 6 (p= 0.0023 and p=0.0016) and in group 3 with respect to groups 1, 4, 5 and 6 (p=0.0023, p=0.0026, p=0.0008 and p=0.0011, respectively). Furthermore, there was a significant decrease in histopathological scores including follicular degeneration, vascular congestion, hemorrhage and inflammation in melatonin and sham groups with respect to control groups. And also, primordial follicle count was significantly higher in group 6 than group 2 (p=0.0002). CONCLUSION Melatonin attenuates ischemia reperfusion damage in rat torsion detorsion model by improving histopathological and biochemical findings including OSI and peroxynitrite.