Betulinic Acid Attenuates Methotrexate Nephrotoxicity by Reducing Oxidative Stress and The Expression of TLR4/NF-Κb Signaling Pathway.

Background: Methotrexate (MTX) is a medication widely used in the treatment of various conditions, including cancer. One potential side effect of MTX is nephrotoxicity. The purpose of the present study was to evaluate the effects of betulinic acid (BA) on MTX-induced nephrotoxicity in mice through the TLR4/NF-κB signaling pathway. Methods: Four groups- control, BA 25 mg/kg, MTX 20 mg/kg, and BA+MTX- were considered for seven days to evaluate the effect of BA on MTX nephrotoxicity. Factors such as blood urea nitrogen (BUN), serum creatinine, antioxidant enzymes, oxidative stress markers, and pro-inflammatory cytokines were investigated. Toll-like receptor 4 (TLR4) and nuclear factor-kappa B (NF-κB) expression levels were measured using Western blot analysis. Results: BUN and creatinine serum levels were significantly reduced in the BA-treated group compared to the MTX group. Furthermore, BA administration inhibited the activation of the TLR4/NF-κB signaling pathway, resulting in reduced expression of TLR4 and NF-κB. This decreased the release of pro-inflammatory cytokines linked to kidney inflammation, such as interleukin-1β and tumor necrosis factor-alpha. Moreover, BA exhibited notable antioxidant properties by enhancing the activity of enzymes like catalase, superoxide dismutase, and glutathione peroxidase. This antioxidant effect was evident by decreasing the levels of oxidative stress markers, as measured by the lipid peroxidation assay, and increasing the total thiol level. Conclusions: These findings suggest that BA can ameliorate MTX-induced nephrotoxicity by reducing oxidative stress and enhancing the antioxidant defense system. It effectively reduces renal damage, inflammation, and oxidative stress. Our results demonstrate that BA's anti-inflammatory and antioxidant qualities could protect the kidneys from MTX's nephrotoxic effects.