Abstract: Objective To observe the effects of cyclophosphamide on the expressions of GDNF and OCT-4 that related functions of spermatogonial stem cells in rats. Methods Twelve 8 weeks male SD rats were randomly divided into control and experimental group. The rats in experimental group were injected cyclophosphamide (50mg?kg-1?d-1) intraperitoneally for three days. The testis and epididymis were removed after 4 weeks of injection to assess the weight , sperm mobility, sperm and spermatogonia numbers and diameter of seminiferous tubule. The expressions of OCT-4 and GDNF were measured by immunohistochemistry assay. Results Compared with the control group, the weights of testis and epididymis were reduced. Although there was no observed changes of testicular histology, the epididymal sperm mobility, and the numbers of epididymal sperm and spermatogonia were reduced. The expression of GDNF was decreased and that of OCT-4 was not changed. Conclusion The spermatogenesis was damaged by short-time treatment of cyclophosphamide, it might be that cyclophosphamide caused the reduction of spermatogonia through the downregulation of GDNF.

Key words: Cyclophosphamide, spermatogenesis, OCT-4, GDNF