The role of nitric oxide in testicular ischemia-reperfusion injury.

Purpose: This study was designed to determine the role of nitric oxide (NO) in the ischemia-reperfusion (I/R) injury process in testes.

Methods: Fifty prepubertal male rats were divided into 5 groups each containing 10 rats. After 4-hour torsion and 4-hour detorsion, bilateral orchiectomies were performed for measurement of tissue malondialdehyde (MDA) level and histopathologic examination. The results were compared statistically. The groups were labeled as group 1, basal values of biochemical parameters in testes; group 2 (control group), torsion plus detorsion; group 3, torsion plus N-monomethyl-L-arginine (L-NMMA) plus detorsion; group 4, torsion plus L-arginine plus detorsion; group 5, sham operation.

Results: The highest MDA values were determined in the L-arginin group in ipsilateral testes. Group 3 and group 4 were statistically different from control group. Histological examination showed that specimens from group 4 had a significantly (P < .05) greater histological injury than group 3, and contralateral testes showed normal testicular architecture in all groups.

Conclusions: These results suggest that NO plays an important role in damaging the testis with I/R. Although inhibition of NO synthesis with L-NMMA significantly improves I/R injury in testes, enhancing NO production by providing excess of L-arginine increases such damage. In the early periods of detorsion, there is no damage to contralateral testes after unilateral testicular torsion.