Lipid peroxidation and antioxidant activities in rat testis after chronic cocaine administration

Our recent study has shown that cocaine has adverse action on spermatogenesis and fertility in male rats. Adverse effects of cocaine on the testes may be mediated by oxidative damage and subsequent lipid peroxidation. Glutathione is a cellular antioxidant and is found in high concentrations in the rat testes. In this study, the effects of chronic cocaine administration on the activities of glutathione peroxidase, the level of testicular reduced glutathione, and lipid peroxidation were investigated.

Thirty-day-old male Sprague-Dawley rats were given cocaine hydrochloride (15 mg/kg body weight) subcutaneously daily for 90 days. Control animals received equal volumes of normal saline daily for 90 days. Testes were removed at 15, 30, 60, and 90 days after cocaine injection. Tissues were washed and homogenized in ice-cold metaphosphoric acid solution or Tris-HCI buffer. Reduced glutathione, glutathione peroxidase, and malonaldehyde levels were determined by colorimetric assay. Statistical analysis was performed using analysis of variance.

Testicular reduced glutathione and glutathione peroxidase were significantly decreased in the treatment testes 15, 30, 60, and 90 days after chronic cocaine injection compared with controls (P <0.05). The testicular malonaldehyde level was 20.8% (P <0.05), 22.1% (P <0.05), 31.2% (P <0.05), and 24.7% (P <0.05) above the control value on days 15, 30, 60, and 90, respectively.

Our findings demonstrate that chronic administration of cocaine to male rats induces a depletion of reduced glutathione and glutathione peroxidase. Adverse effects of cocaine on the testes are at least in part due to impairment of the function of the antioxidant defense and further enhancement of lipid peroxidation.