RESUMO
Methadone (Met) is the most common treatment for opioid addiction. Although Met is effective for treatment of opioid dependence, sexual dysfunctions and infertility have been reported as a major problem in patients under Met treatment. The present study aimed to evaluate the effect of melatonin and N-acetylcysteine (N) on morphine and Met-induced oxidative stress, apoptosis, suppression of blood sexual hormones, impairment in sperm parameters, and sexual dysfunction. Adult male Wistar rats (n = 66) were randomly divided into 11 equal groups (n = 6) as follows: control, sham, morphine, Met, Met+N, Met+ melatonin, Met+melatonin+N, morphine+ Met, morphine+Met+ melatonin, morphine+Met+N, and morphine+Met+ melatonin+N groups. On day 56 post-treatment, the blood was collected from the tail and the serum levels of sex hormones were evaluated, then the rats were sacrificed, and their bilateral testes and epididymis were retrieved for histological, immunohistochemical, molecular, testicular tissue stress oxidative status, and sperm parameters assays. Exposure to morphine, Met, and shift of morphine to Met resulted in testicular degeneration that can be attributed to generating the stress oxidative-induced- apoptotic testicular cell death and impairing spermatogenesis. Melatonin and N alone and particularly, in combination with each other improved testicular degeneration, sex hormone suppression, and testicular function mediated by increasing the testicular antioxidant capacity and inhibition of the apoptosis pathway. It's suggested that oral administration of antioxidants may be an effective treatment for attenuating some opioid-related testicular dysfunction and degeneration.