The influence of in vivo exposure to nonylphenol ethoxylate 10 (NP-10) on the ovarian reserve in a mouse model

Aim: To determine the effect of nonylphenol-ethoxylate-10 (NP-10) on the ovarian reserve in a mouse model.

Design: Female mice were maintained on purified water or exposed to NP-10 from 3-7-weeks of age. At 7-weeks they were stimulated, mated and the zygotes were cultured in-vitro. Three and 7-weeks old mice were untreated controls. Identical groups were sacrificed without stimulation. Ovaries were analysed for follicular composition. Respiratory-chain (RC) activity and reactive-oxygen-species (ROS) production were measured in brains and livers.

Results: Seven-weeks-old mice produced fewer oocytes/embryos than 3-week-old mice. At 7-weeks, mice exposed to NP-10 produced more oocytes/embryos the controls. Their ovaries contained more primordial/primary follicles, with a lower rate of proliferation and fewer antral follicles. There were no differences in follicular apoptosis, RC-activity or ROS production.

Conclusions: In this model, exposure to NP-10 inhibited the spontaneous follicular recruitment, the first report of successful inhibition of physiologic ovarian aging, to the best of our knowledge.