OBJECTIVETo investigate the occurrence of germ cell apoptosis and the expression of Bcl-2/Bax after aniso-doses arsenic (As2O3) administration in the testes of the adult male rats.

METHODForty healthy male Sprague-Dawley rats were divided randomly into four groups and were administered respectively with 0 (control group), 0.375, 0.75, 1.5 mg x kg(-1) of As2O3 by intragastric administration consecutively for 16 weeks. The numbers of testicular sperm head were counted and the coefficient of testicular viscera and daily sperm production (DSP) were calculated in every group. The apoptosis of germ cell were assessed by in situ terminal deoxynucleotityl transferase mediated dTUP nick end labeling (TUNEL) technique. The expression of Bel-2/Bax in spermatogenic cells of different grades were located and quantitated by the method of immunohistochemistry.

RESULT(1) In the testes of As2O3-treated rats, the coefficient of testicular viscera, the number of testicular sperm head and DSP in the middle and high dose groups decreased significantly, compared with those in the control group (P < 0.01); however the apoptosis index of germ cell (AI) significantly increased compared with that in the control group (P < 0.01). Bcl-2 expression of middle dose group and high dose group decreased significantly compared with that in the control group (P < 0.01). Bax expression of middle dose group and high dose group increased significantly compared with that in the control group (P < 0.01); (2)The dependability analysis between DSP and AI showed a negative correlation (r = -0. 563, P <0. 01). (3) The negative correlation was significant between AI and Bcl-2 expression of spermatogenic cells (r = -0.825, P < 0.01); The positive correlation was significant between AI and Bax expression of spermatogenic cells (r = 0.710, P < 0.01).

CONCLUSIONOne of the mechanisms of male reproduction toxicity of As2O3 might be that Bcl-2 expression is inhibited and Bax expression is encouraged which induces the decrease of quantity of sperm cells.