In vivo exposure to pyriproxyfen causes ovarian oxidative stress and inhibits follicle maturation in zebrafish

We analyzed the effects of pyriproxyfen (PPF) on oxidative stress and ovarian morphology in zebrafish. PPF (10(-9) M) exposure increased reactive oxygen species generation in ovaries, in association with a decrease in glutathione content. The activities of glutathione S-transferase, superoxide dismutase, and catalase were increased, while gamma-glutamyltransferase activity was not altered by pesticide treatment. The histology of ovarian tissue showed an increase in the number of previtellogenic oocytes I, and a decrease in the rate of vitellogenic oocyte (VIT) count, suggesting inhibition of follicular maturation. An increase in the thickness of the vitelline envelope was observed in VIT, as was a tendency toward an increase in atresia in the ovary of the PPF-treated group. These findings indicate that the deleterious effect of PPF on ovarian maturation is mediated by a redox imbalance and oxidative damage. So, PPF acts as an endocrine disruptor chemical and may compromise fish reproduction by reducing female fertility.