Epidemiological surveys and animal experiments have shown that
2-bromopropane induces
oligozoospermia in exposed workers and inhibits spermatogensis in laboratory animals. However, the mechanism by which
2-bromopropane exerts its effects is unknown. To this end, we examined the formation of
testosterone by the Leydig cells and their survival of these cells in the presence of different concentrations of
2-bromopropane in vitro. Leydig cells were isolated following vascular perfusion, enzymatic dissociation and
Percoll gradient centrifugation techniques. The cells were cultured in culture dishes. After 8 h, different cultures were exposed to
2-bromopropane at concentrations of 0.01 mmol/L, 0.10 mmol/L and 1.00 mmol/L. In order to stimulate Leydig cells to secrete
testosterone,
human chorionic gonadotropin (hCG) was also added. Cell viability was determined using the
trypan blue dye exclusion test and cell numbers were counted by hemocytometer.
Testosterone secretion was detected by radioimmunoassay. The cell viability decreased after exposure to
2-bromopropane in a dose-dependent way, but no morphological change was observed. The cell number decreased in the 2-bromopropane-treated cultures. The secretion of
testosterone did not manifest defectable changes in the culture treated with 0.10 mmol/L and 0.01 mmol/L of 2-bromopropane; however, it decreased significantly (P < 0.02) in the presence of 1.00 mmol/L. Therefore, our results strongly suggest that
2-bromopropane may exert its cytotoxic effects on Leydig cells in vitro. We speculate that the decrease in the numbers of Leydig cells caused by
2-bromopropane was mediated by a feedback mechanism resulting from a lower
testosterone concentration.