Objective     To study the toxicity of organic extract from river water on the male reproductive system in rats.      Methods     Organic pollutants were extracted from river water with XAD-2 resin and the extract from 2

16 and 80 L river water was administered daily into 30 male SD rats by gavage for consecutive 28 days. Corn oil served as the solvent control in another ten rats. After the last intake of water extract

all rats were killed

and the sections of testis were prepared according to routine procedure. The TUNEL assay for in situ detection of apoptosis and quantitation of apoptotic germ were performed on testicular sections. Immunohistochemistry and Western blotting were used to examine the changes of scf

fas

fasL and c-kit expressions in rat testis.      Results     The percentage of apoptotic spermatid cells significantly increased in rats receiving organic extract from 80 L water daily

as compared with the control rats. The spermatocytes in rats receiving organic extract from 80 L water daily overexpressed fas

fasL and c-kit.      Conclusion     The organic pollutants from river water result in spermatid apoptosis and spermatogenesis arrest.