Additive effect of Bisphenol A and Pefluoro-sulphoctanoic acid exposure at subacute toxic levels, on a murine model of sertoli cell

Purpose: Endocrine disruptors (EDs) interfere with the endocrine system leading to health consquences and reproductive derangements. Most EDs are environmental pollutants whose risk evaluation is hampered by the simultaneous exposure to a number of chemicals. Here we investigated the possible mechanistic involvement of Sertoli cells, the nurse cell population in the seminiferous tubule, in the reproductive toxicity of Bisphenol A (BPA) and perfluoro-octane sulphonate (PFOS), two acknowledged EDs, at recognized subacute toxic levels.

Methods: Mouse Sertoli cell line TM4 were exposed for 24 h to 40 ng/mL BPA or 30 ng/mL PFOS or their association. Cell proliferation was measuerd by MTT assay. Cell apoptosis was evaluated with Annexin-V/propidium iodide staining. Protein expression analysis was peformed by western blotting.

Results: Compared to unexposed controls (100.0 ± 3.5%), cells exposed to BPA (79.5 ± 3.5%) or PFOS (76.0 ± 7.9%) showed reduced survival rate (P < 0.001 vs control). The exposure to the mixture of BPA and PFOS was associated with a further reduction of cell survival (63.9 ± 7.2%, P < 0.001 vs control) and an increase of the percentage of apoptotic cells (13.7 ± 4.6% control, 40.3 ± 13.5% BPA, PFOS 28.7 ± 5.6%, 67.1 ± 19.6% BPA + PFOS P = 0.001 vs control; P = 0.022 vs BPA). The exposure to the combination of BPA and PFOS was associated with Akt-signaling pathway activation and with the downstream caspase 3 cleavage. In addition, the exposure to the combination of BPA and PFOS was associated with NF-κB activation and increased expression of FasL.

Conclusion: Subacute toxic levels of BPA and PFOS display additive effects on Sertoli cell apoptosis with the possible involvement of FasL-dependent germ cell apoptosis.