Possible direct cytoxicity effects of cyclophosphamide on cultured human follicles: An electron microscopy study

Purpose: To evaluate the direct effect of cyclophosphamide on cultured human ovarian follicles. Methods: Human ovarian cortical slices from premenopausal women were incubated with medium containing cyclophosphamide (0.0005-0.5 mg/mL) for 2-48 h and assessed by transmission electron microscopy. Noncultured specimens and samples cultured without cyclophosphamide were used as controls. Results: There were significantly more damaged granulosa cell nuclei after incubation with 0.5 mg/mL cyclophosphamide for at least 4 h. There were also more changes in the basement membrane after incubation with cyclophosphamide at concentrations of 0.05 and 0.5 mg/mL. Conclusions: Although the cyclophosphamide dose that caused damage to the granulosa cell nuclei was above the pharmacological level, our results suggest that cyclophosphamide, and not only its active metabolite phospharamide mustard, might have a destructive effect on human follicles, as it remains in the circulation longer. This effect could be mediated by damage to the granulosa cells and perhaps the basement membrane.