Beneficial effects of melatonin compared with allopurinol in experimental testicular torsion.

Background/purpose: Several antioxidant agents such as allopurinol have been used to prevent ischemia-reperfusion (I/R) injury-induced tissue damage after experimental testicular torsion so far. The current study was designed to determine the effect of melatonin, which is a potent antioxidant agent, in preventing testicular damage following torsion.
Methods: Sixty prepubertal male Wistar-Albino rats were divided into 5 groups: control (C), torsion (T), torsion plus detorsion (TD), torsion plus allopurinol (200 mg/kg) plus detorsion (A), and torsion plus melatonin (50 mg/kg) plus detorsion (M). Left testes were rotated 720 degrees for 6 hours. The torsed testes were detorsed. Detorsion time was 6 hours. In all groups, left orchiectomies were performed to determine the tissue levels of malondialdehyde (MDA) and histopathologic changes. Blood samples were taken to measure serum creatine phosphokinase (CPK) levels. The results were analyzed statistically.
Results: Serum CPK levels of groups A and M were found to be significantly lower than groups T and TD (P <.05). Tissue MDA levels in group M were statistically different from groups T and TD (P <.05). However, in groups A and T, MDA levels were similar (P >.05). The highest histologic grade was determined in group TD (3.8 +/- 0.5). Histologic grade of group M was significantly lower than group TD (P <.001), but there was no histologic difference between testes of groups A and TD (P >.05).
Conclusions: These results have shown that melatonin treatment prevents I/R injury both biochemically and histopathologically, whereas allopurinol treatment prevents it only biochemically in experimental testicular torsion. Melatonin is a potent antioxidant agent more effective than allopurinol in preventing testicular I/R injury.