The effect of "activated" cyclophosphamide on rat granulosa cells in vitro

We investigated the mechanism of cyclophosphamide (CTX)-induced ovarian toxicity by studying the effect of an activated form, 4-hydroperoxycyclophosphamide (PCTX), on rat granulosa cells in vitro. Cells were obtained from PMSG-primed immature rats and incubated with PCTX at concentrations of 1, 10, 100, and 500 micrograms/mL. Ovine LH (10 ng/mL) was added in selected tubes. Cell viability before and after seven hours incubation was determined. Progesterone and prostaglandin E accumulation were measured by radioimmunoassay. Granulosa cell viability was significantly decreased at PCTX concentrations of 10 micrograms/mL or higher in a dose-related manner. PCTX at concentrations of 100 micrograms/mL and 500 micrograms/mL significantly decreased basal and LH-induced progesterone and prostaglandin E accumulation. The above findings demonstrate that cyclophosphamide metabolites decrease granulosa cell survival and function in vitro. These direct effects suggest a possible mechanism for CTX-induced premature ovarian failure.