Cytotoxic effects of cyclophosphamide in the mouse seminiferous epithelium: DNA flow cytometric and morphometric...

Stage-specific cytotoxicity of cyclophosphamide (CP) in the mouse testis was analyzed by quantitative DNA flow cytometry and morphometry. In five series of experiments, three mice were injected (ip) with either a single dose of CP at 30 mg/kg or a vehicle saline. At 3, 11, and 20 days later, spermatogenic cells from stages II-V, VII-VIII, and IX-XI of the seminiferous epithelial cycle were quantified by flow cytometry and by morphometry. CP killed a part of the differentiating spermatogonia which became apparent at 11 days when the number of panchytene spermatocytes at stages II-V and VII-VIII was decreased. At stages IX-XI, the number of leptotene and zygotene spermatocytes declined at this time point. These damages could be detected by morphometry, while flow cytometry showed only the trend of the difference. At 20 days, both methods revealed a decrease in the number of haploid spermatids at stages VII-VIII (48 and 33% decrease detected by morphometry and flow cytometry, respectively). DNA flow cytometry proved to be a rapid and practical method to detect stage-specific disruption of spermatogenesis, while morphometry was more sensitive.