M. Estefanía González-Alvarez¹, Samantha L. Good², Joseph A. Charbonnet², Aileen F. Keating¹ 

¹Department of Animal Science, Iowa State University, Ames, IA, 50011, USA 

²Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA, 50011, USA 

Perfluorooctanoic acid (PFOA) is associated with negative reproductive effects, including altered menopause onset, decreased ovarian reserve, delayed puberty onset and vaginal opening, and decreased ovarian steroidogenesis. Our previous work found that PFOA altered the ovarian abundance of chemical biotransformation proteins. To test the hypothesis that PFOA exposure changes the ovarian biotransformation microenvironment, we employed the polycyclic aromatic hydrocarbon 7,12-dimethylbenz[a]anthracene (DMBA), which is biotransformed first in the ovary to DMBA-3,4-diol and subsequently to the ovotoxic metabolite DMBA-3,4-diol-1,2-epoxide via CYP1A1. Exposure to DMBA induces ovarian DNA damage and follicle loss. This research investigated whether PFOA exposure would impact the previously characterized ovotoxicity caused by DMBA exposure. C57BL/6J female mice at seven weeks of age received one of three treatments: 1) saline solution as vehicle control (CT; n = 10), 2) PFOA (2.5mg/kg; 2.5ppm; n = 9) per os for 15 d, and 3) PFOA (2.5mg/kg; 2.5ppm) per os for 15 d and during the last 7 d, DMBA (1 mg/kg) via intraperitoneal injection (PFOA + DMBA; n = 10). Body weight was monitored twice weekly, and mice were euthanized on the second day of diestrus. Final body weight and tissue weights were recorded. Statistical analyses were performed using GraphPad Prism 10.1.2 software. Final body weight, heart, spleen, kidney, and ovarian weight were decreased (P < 0.05) by PFOA exposure alone or in combination with DMBA. Uterus weight was decreased (P < 0.05) only by PFOA + DMBA exposure. Liver weight was increased (P < 0.05) by PFOA exposure alone or together with DMBA. UHPLC-tandem mass spectrometry quantified the amount of PFOA partitioned to the ovary and PFOA-treated mice had detectable ovarian PFOA level compared to controls (P < 0.05). The amount of PFOA in ovaries of mice treated with both PFOA and DMBA was lower than in those treated with PFOA alone. A serum mammalian liver panel determined that alanine aminotransferase and urea nitrogen were increased (P < 0.05) by PFOA exposure alone but not by PFOA combined with DMBA, while total bilirubin was decreased (P < 0.05) by PFOA exposure alone but not by PFOA combined with DMBA. Ovarian protein abundance of PPARα, PPARγ, TLR4, CYP19A1, AKT, pAKT, and ERβ were decreased (P < 0.05) by both PFOA exposure alone and PFOA combined with DMBA. Ovarian abundance of CYP1B1 and CYP11A1 was decreased (P < 0.05) only by PFOA exposure. These data, taken together, support that PFOA partitions to the ovary and alters the ovarian microenvironment to impact the ovarian effects of a co-toxicant exposure.