Exposure to 3-methyl-4-nitrophenol affects testicular morphology and induces spermatogenic cell apoptosis in immature male rats

The pollutant 3-methyl-4-nitrophenol (PNMC), a major component of diesel exhaust particles, can cause many adverse health problems. In the present study, we investigated the effects of PNMC on the testes of Sprague Dawley rats treated subcutaneously for 5 days with different doses of PNMC (1, 10 or 100 mg/kg). Exposure to PNMC caused a significant decrease in the plasma testosterone levels and in the absolute and relative weights of the testes. Severe histological lesions were observed in the testes of PNMC-treated animals. The ratio of the epithelial height to the seminiferous tubule diameter increased markedly in the PNMC-treated rats compared with the corresponding controls. In addition, PNMC exposure significantly increased the number of apoptotic spermatogenic cells compared with the controls whereas a significant decrease in the ratios of Bcl-2/Bax was observed at the same doses. These results suggest that PNMC exerts its gonadotoxicity in the rat mainly via apoptosis.