Excessive fluoride induces ovarian function impairment by regulating levels of ferroptosis in fluorosis women and ovarian granulosa cells.

The aim of this study was to investigate the role of ferroptosis in fluorosis women and the in vitro molecular mechanisms leading to ovarian dysfunction and abnormal hormone secretion by sodium fluoride (NaF) treatment of KGN cells. Fifty women with fluorosis as Fluorosis group and fifty healthy women as Control group were included in this study. The levels of lipid peroxidation and activities of antioxidant enzyme were assessed by photometric methods. The content of iron and glutathione (GSH) in serum was measured by microplate method. KGN cells were treated by different concentration of NaF (0, 1, 2, 4 and 8×10-3 M) for 24h. The mRNA and protein expression levels of ferroptosis-related molecules, including glutathione peroxidase 4 (GPX4), solute carrier family 7 member (SLC7A11), nuclear factor erythroid 2-related factor 2 (Nrf2), ferritin heavy chain 1 (FTH1) and p53, were assessed by qRT-PCR and western blot analysis. Fluorosis group women had a significant higher levels of iron, Malondialdehyde (MDA), FSH and LH, and a lower levels of E2 and antioxidant enzyme in serum than that in the control group. The representative molecular changes of ferroptosis, such as the decrease in GPX4, Nrf2 and SLC7A11 expression (mRNA and protein expression), the increase in protein expression of p53, and a reduced level of E2 were observed in KGN cells treated by excessive NaF. It is concluded therefore that NaF increases the expression of p53 and inhibits ovarian granulosa cell ferroptosis preventive protein expression, resulting in abnormal hormone secretion and the ovarian dysfunction.