Effect of naloxone on oxidative stress and testicular injury due to spermatic vessel ligation of rat testis.

Aims: Two-stage Fowler-Stephens orchiopexy has been accompanied by testicular atrophy in some cases but neither of the mechanisms responsible for testicular injury are clear, nor is there an effective agent that might prevent this injury. In this study we aimed to investigate the long-term effects of naloxone, a morphine antagonist, on testicular histopathology and oxidative stress after spermatic vessel ligation (SVL) in rats.
Methods: 32 prepubertal rats were randomly divided into four equal groups: group 1: control (only bilateral orchiectomies were performed); group 2: sham-operated group; group 3: SVL, and group 4: SVL+naloxone (1 mg/kg twice daily for 1 month). One month postoperatively, bilateral orchiectomies were performed to evaluate histopathologic findings and measurement of malondialdehyde (MDA) and nitric oxide (NO) levels.
Results: Considering group 3, left SVL resulted in significant tissue damage in both testes, more severe in the ipsilateral testis. The SVL resulted in a significant increase in testicular MDA levels of both testes in this group (p < 0.05). While the ipsilateral testicular NO levels of groups 2 and 3 were significantly lower than of group 1 (p < 0.05), the contralateral testicular NO levels of all these groups were similar. After naloxone therapy, while there was no significant improvement in ipsilateral testicular histopathology (p > 0.05), the contralateral testicular histopathology improved significantly (p < 0.05). However, naloxone did not change either testicular MDA or NO levels.
Conclusions: The SVL led to bilateral testicular injury, and oxidative stress may be a reason for this injury. Naloxone significantly improved contralateral testicular injury without showing any antioxidative effect.
(2008 S. Karger AG, Basel)