RÉSUMÉ
<p><b>OBJECTIVE</b>To perform a preliminary study on the dysfunction of spermatogonial stem cells (SSCs) induced by cyclophosphamide.</p><p><b>METHODS</b>According to development stage of spermatogenesis in Wistar rat, 72 rats were divided into three groups, 1, 3 and 9 weeks groups, respectively. Then 24 rats per group were randomly divided into experimental and control groups, and 100 mg/kg cyclophosphamide was injected by intraperitoneal injection in experimental groups, with the same volume of normal saline in the control. Apoptosis of spermatogenic cells were detected after 24 hours by TUNEL. Then 60 one-week rats, whose germ cells were only SSCs, were randomly divided into experimental and control group. We detected c-Kit by immunohistochemistry and cell cycle by flow cytometry at 24 hours, 3 and 9 weeks.</p><p><b>RESULTS</b>There was no significant difference in apoptosis of germ cells in 1 week between experimental group and control group ( P > 0.05); however, there were significant differences among other groups. The ratio of S stage and c-Kit expression of spermatogonial cells were decreased in one-week rats at 24 hours, 3 and 9 weeks in experimental group compared with the control, respectively (P < 0.01).</p><p><b>CONCLUSION</b>Cyclophosphamide does not significantly induce SSCs apoptosis. It may be more important to interfere the proliferation and differentiation of SSCs.</p>