Abstract: BACKGROUND ＆ AIM: To study Bcl-2 and Bax expressions in spermatogenic cells, ultrastructural changes in spermatogenic cells and sperms of mice after exposure to mercury. MATERIALS AND METHODS: 32 male mice were divided into 4 groups,3 groups treated with intraperitoneal mercuric chloride of 0.5,1.0,5.0 μmol/(kg•d) for 5 days,and one normal saline control group.The positive expression rates of Bcl-2 and Bax protein and average optical density in spermatogenic cells by the immunohistochemical method were assayed, and the ultrastructural changes of spermatogenic cells and sperms were assessed by the transmission electron microscope. RESULTS: Bcl-2 protein expression positive rates and average optical density were lower than of normal group(P<0.05).Bax protein expression positive rates and average optical density in 1.0,5.0 μmol/kg groups were higher than those in normal group (P<0.05).The ultrastructure of nuclear membrane,chromatin,mitochondria and sperm mitochondria in three treated groups showed different degrees of injury and the degree of ultrastructural change was more severe with increasing concentration of mercury. CONCLUSION: Mercury exposure caused abnormal Bcl-2 and Bax protein expression, average optical density change and ultrastructural changes in spermatogenic cells and sperms.

Key words: mercuric chloride, Bcl-2, Bax, spermatogenic cell, sperm, ultrastructure