Nrf2 Signaling Elicits A Neuroprotective Role Against PFOS-mediated Oxidative Damage In Rat Hippocampal Neurons And SH-SY5Y Cells

Objective To investigate the protective role of Nrf2 signaling pathway in PFOS-induced neuronal apoptosis.Methods1.(1)In this study,24 SPF adult Sprague-Dawly(SD)rats(6-week)were randomly divided into 3 groups with 8 rats in each group: control group(PFOS: 0 mg/kg),low-dose group(PFOS: 1 mg/kg),high dose group(PFOS: 10 mg/kg).PFOS dissolved in 0.5%Tween-20,administered by gavage for 28 days,weighed daily,and adjusted the dose according to the rat weight change.Establishing the PFOS-exposed animal model.(2)After the modeling is completed,the rat brain tissue of rats were sugically resected for subsequent analysis.(3)HE staining was used to determine the morphological changes of hippocampus in rats,and the protein expression of bax and bcl-2 was analyzed by Western blotting.(4)Western blot,immunohistochemistry and immunofluorescence analyses were employed to examine the effect of PFOS on the expression and localization of Nrf2 signaling pathway-related proteins in rat brain tissue.Results1.(1)HE staining showed that PFOS caused hippocampal neuronal damage,which was characterized by cell shrinkage,disordered arrangement and appearance of black cells.Western blot results showed that the expression of bax protein in rat brain tissue was up-regulated in a dose-dependent manner and the expression of bcl-2 protein was decreased in a dose-dependent manner(P<0.05).(2)Western blot,immunohistochemistry and immunofluorescence assay showed that PFOS induced the activation of Nrf2 signaling pathway in rat brain tissue.2.(1)Western blotting showed that the Nrf2 pathway was activated in a dose-and time-dependent manners in PFOS-exposed SH-SY5 Y cells,and the levels of apoptosis-related proteins were dose-dependently increased(P<0.05).(2)Microscopically,PFOS caused cell morphology shrinkage and rounding,and cell activity decreased in a dose-dependent manner(P<0.05).(3)ROS detection analysis uncovered PFOS-induced increase in ROS production in cells(P<0.05).3.(1)Western blotting assay showed that NAC could inhibit the expression of apoptosis-related proteins induced by PFOS and attenuate the activation of PFOS-induced Nrf2 signaling pathway.Cellular fluorescence showed that NAC hindered PFOS-induced nuclear translocation of Nrf2(P<0.05).(2)ROS increased in brusatol pretreatment+PFOS group compared to PFOS alone exposed group.(3)NAC pretreatment can attenuate mitochondrial damage,apoptosis-related protein activation and cell damage induced by PFOS,while brusatol pretreatment aggravates these phenomena.Conclusions1.PFOS exposure can cause damage to rat hippocampal neurons and SH-SY5 Y cells and activate the Nrf2 signaling pathway.2.Neuronal cell damage induced by PFOS is closely related to changes in mitochondrial membrane potential and damage to mitochondrial morphology.3.Inhibition of Nrf2 signaling pathway aggravates PFOS-induced cell injury,suggesting that Nrf2 signaling pathway have protective effects in PFOS-induced neurotoxicity.