Neuroprotective effects of 18 beta-glycyrrhetinic acid against bisphenol A-induced neurotoxicity in rats: involvement of neuronal apoptosis, endoplasmic reticulum stress and JAK1/STAT1 signaling pathway

Abstract

The exposure to bisphenol A (BPA) is inevitable owing to its common use in the production of polycarbonate plastics. Studies to reduce side effects are gaining importance since BPA causes severe toxicities in important tissues such as testes, lungs, brain, liver and kidney. The current study was planned to study ameliorative effect of 18 beta-glycyrrhetinic acid (18 beta-GA) on BPA induced neurotoxicity. Fourty Wistar albino rats were divided into five equal groups as follows: I-Control group, II-18 beta-GA group (100 mg/kg), III- BPA group (250 mg/kg), IV-250 mg/kg BPA +50 mg/kg 18 beta-GA group, V-250 mg/kg BPA +100 mg/kg 18 beta-GA group. BPA intoxication was associated with increased MDA level while reduced GSH concentration, activities of glutathione peroxidase, superoxide dismutase, and catalase. BPA supplementation caused apoptosis in the brain by up-regulating caspase-3 and Bax levels and down-regulating Bcl-2. BPA also caused endoplasmic reticulum (ER) stress by increasing mRNA transcript levels of PERK, IRE1, ATF-6 and GRP78. Additionally, it was observed that BPA administration activated JAK1/STAT1 signaling pathway and levels of TNF-alpha, NF-kappa B, p38 MAPK and INK in the brain. However, co-treatment with 18 beta-GA at a dose of 50 and 100 mg/kg considerably ameliorated oxidative stress, inflammation, apoptosis, ER stress and JAK1/STAT1 signaling pathway in brain tissue. Overall, the data of this study indicate that brain damage associated with BPA toxicity could be ameliorated by 18 beta-GA administration.