The protective effects of nitric oxide on the contralateral testis in prepubertal rats with unilateral testicular torsion

Objective To investigate histological changes in the contralateral testis o f rats with unilateral testicular torsion and the protective effects of nit ric oxide (NO) on possible damage. Material and methods Twenty-eight prepubertal male Sprague-Dawley rats were divided into four equal groups. Group 1 underwent a sham operation of the right testis under general anaesthesia. Group 2 underwent a similar operati on but the right testis was rotated 720 degrees clockwise for 6 h, maintain ed by fixing the testis to the scrotum, and saline infused during the proce dure. Group 3 underwent similar torsion but L-arginine methyl ester (a prec ursor of NO) was infused during the procedure. In Group 4, N-G-nitro-L-argi nine-methyl ester, a NO synthase inhibitor, was infused separately during t he administration of L-arginine methylester and torsion. All the left (untw isted) testes were removed from rats 21 days after surgery and evaluated hi stologically, assessing seminiferous tubule diameter, loss of sperm and spe rmatids, loss of germ cell layers, disarray of germ cell layers, rupture of tubules, Leydig cell proliferation and reaction in the ruptured tubules, a nd oedema. Results There was a significant difference in the indicators of histologica l damage between groups 2 and 4 and groups 1 and 3, except for the Leydig c ell reaction in the ruptured tubules and oedema. The damage was significant ly less in group 3 than in groups 2 and 4. Conclusion These results suggest that long-term histopathological changes i n the contralateral testes are important after unilateral testicular torsio n and that NO has a protective effect on the contralateral testis.