Fluorene-9-bisphenol exposure induces cytotoxicity in mouse oocytes and causes ovarian damage

Fluorene-9-bisphenol (BHPF), a substitute for bisphenol A, is a chemical component of plastics for industrial production. There is evidence that BHPF exerts an antioestrogenic effect on mice, induces endometrial atrophy and leads to adverse pregnancy outcomes. However, the effects of BHPF on oocyte maturation and ovary development as well as its possible mechanisms remain unclear. The objective of this study was to investigate the toxicity and mechanism of BHPF exposure in mouse oocytes in vitro and in vivo. Our results showed that BHPF could inhibit the maturation of oocytes in vitro by reducing the protein level of p-MAPK and destroying the meiotic spindle. We found that in vitro, BHPF-treated oocytes showed increased ROS levels, DNA damage, mitochondrial dysfunction, and expression of apoptosis- and autophagy-related genes, such as Bax, cleaved-caspase 3, LC 3 and Atg 12. In addition, in vivo experiments showed that BHPF exposure could induce the expression of oxidative stress genes (Cat, Gpx 3 and Sod 2) and apoptosis genes (Bax, Bcl-2 and Cleaved-caspase 3) and increase the number of atresia follicles in the ovaries. Our data showed that BHPF exposure affected the first polar body extrusion of oocytes, increased oxidative stress, destroyed spindle assembly, caused DNA damage, altered mitochondrial membrane potentials, induced apoptosis and autophagy, and affected ovarian development.