Human fetal testes were recovered during the first trimester (7-12 weeks) of gestation and cultured in the presence or not of 10鈭?#xA0;5 M MEHP for three days. Apoptosis was quantified by measuring the percentage of Caspase-3 positive germ cells. The concentration of phthalate reaching the fetal gonads was determined by radioactivity measurements, after incubations with 14C-MEHP.
A 10鈭?#xA0;5 M exposure significantly increased the rate of apoptosis in human male fetal germ cells. The intratesticular MEHP concentration measured corresponded to the concentration added in vitro to the culture medium. Furthermore, a comparable effect on germ cell apoptosis in mouse fetal testes was induced both in vitro and in vivo.
This study suggests that this 10鈭?#xA0;5 M exposure is sufficient to induce changes to the in vivo development of the human fetal male germ cells.