Modulation of TLR4 and upregulation of HO-1 & PPAR-γ by Pioglitazone ameliorates methotrexate-induced liver damage in rats

Abstract Background Methotrexate is a frequently prescribed antifolate immunosuppressant and antineoplastic agent that has been associated with serious systemic adverse effects including hepatotoxicity. The current investigation explored the efficacy of the peroxisome proliferator activated receptor-gamma (PPAR-γ) agonist, Pioglitazone, in modulating Methotrexate-provoked liver damage then elucidating the underlying molecular mechanisms. Rats were allocated into four groups ( n = 6): control group (received saline orally); Pioglitazone-exposed group (administered Pioglitazone 4 mg/kg/day p.o. from day 15 to 28); Methotrexate-treated group, (received Methotrexate 14 mg/kg/week p.o. from day 1 to 14); and Methotrexate and Pioglitazone-treated group (received Methotrexate form day 1 to 14 then received Pioglitazone from day 15 to 28 at the previously specified doses). Results The findings of the current work demonstrated that Pioglitazone alleviated Methotrexate-induced liver injury as depicted by correcting Methotrexate-induced elevation of liver enzymes, namely, alanine aminotransferase plus aspartate aminotransferase as well as ameliorating Methotrexate-induced histopathological changes. Accordingly, Pioglitazone administration in Methotrexate-intoxicated rats partially restored the redox homeostasis as manifested by suppressing malondialdehyde alongside elevating reduced glutathione contents. Notably, all previously mentioned parameters were measured using colorimetric assays. Remarkably, the reported hepatoprotective effect is putatively mediated through hindering hepatic inflammation reflected by the reported upregulation of PPAR-γ and hemoxygenase-1 with subsequent suppression of nuclear factor-kappa B and tumor necrosis factor-α. Additionally, current findings revealed modulation of Toll-like receptor 4 following Pioglitazone treatment that was further confirmed by our in silico study. Conclusions Therefore, this investigation suggests Pioglitazone as a promising therapeutic intervention in mitigating Methotrexate-induced liver injury.