Perinatal Exposure to Bpa and BPS Can Alter the Sexual Behaviour and Reproductive System of Offspring

Bisphenols are compounds used in industrial processes to create everyday products, such as plastics for food packaging and polycarbonates. These substances are recognized as Endocrine Disruptors (EDs) because they interfere with the endocrine system by impacting hormone synthesis and action, which can alter organ development, reproductive health, and metabolic processes, especially during sensitive periods of life. This establishes a direct route for human exposure, posing potential risks for pregnant women and their babies. The purpose of this study was to assess how maternal perinatal exposure to two EDs, Bisphenol A (BPA) and Bisphenol S (BPS), can affect the sexual behavior and reproductive system of F1 males and females in adulthood. The doses were selected based on the latest TDI (tolerable daily intake) established by EFSA. CD1 mouse mothers were orally treated during pregnancy and lactation and divided into three groups: 1) control, 2) BPA (0.2 ng/kg), and 3) BPS (0.2 ng/kg). Pups were monitored during all stages of development for weight and food intake, and after weaning, their onset of puberty was also evaluated daily, during which we observed a delay in entry into BPA females. Once they reached adulthood, at around postnatal day (PND) 90, they were subjected to various behavioural tests, sexual behaviour and Y-maze using litters, to assess their sexual and social behaviours. At PND120, animals were sacrificed to allow histological and molecular tissue analyses. The results of both these tests showed altered behaviour in the treated animals compared to the control groups. Sexual behavior showed a reduction in sexual interest in the treated F1 animals, as determined by a decrease in lordosis and a higher rejection rate of males by females, as well as almost no attempts to mount and intromit in males. The Y-maze revealed an inversion in sexual preference in BPA and BPS animals compared to control animals; in fact, during the analysis, a lower latency and a higher duration in the arm with litter of the same sex as the tester animal was observed, so males had a preference for male litter and females for female litter leading to an inversion of the natural behaviour observed in control animals. In collaboration with the research team at the University of Padova, the testes of F1 males were examined to evaluate their function and to interpret the data from behavioral tests. Results from bioaccumulation studies of BPA and BPS, measured by LC-MS, indicated that these substances accumulate more in the testes than in plasma, leading to decreased sperm motility in treated animals compared to controls. Additionally, hormone analysis in plasma showed reduced levels of testosterone and INSL3 in both exposed groups, while FSH and LH levels were higher in exposed mice relative to controls. Protein expression analysis in the testis revealed an increased FSH receptor in both ED-exposed groups. Regarding females, ovaries and fallopian tubes are still being analyzed with the University of Naples research team. Future studies will include immunohistochemical analyses of the brain, focusing on markers related to these behaviors. In conclusion, the results obtained show that perinatal exposure to the latest TDI of BPA and BPS can influence the sexual behaviour and reproductive system of the offspring, leading to a dysfunction of the latter in males and an alteration of the sexual instinct in both males and females of the exposed groups.