Comparative hepatoprotective effects of Ginkgo biloba extract and N-Acetylcysteine against methotrexate-induced liver injury in rats: modulation of IκB-α, p38 MAPK, and p53 phosphorylation.

Methotrexate (MTX) is an effective chemotherapeutic agent whose use can be limited by hepatotoxicity. This study comparatively evaluated the effects of Ginkgo biloba extract (GbE) and N-acetylcysteine (NAC) on MTX-induced liver injury, focusing on oxidative stress, inflammatory and apoptotic responses, and associated hepatic phosphorylation of Inhibitor of nuclear factor kappa-B alpha (IκB-α), p38 mitogen-activated protein kinase (p38 MAPK), and tumor protein p53 (p53), key components of stress-responsive signaling pathways. Thirty-two adult male rats were randomly assigned to four groups (n = 8/group). MTX (20 mg/kg, i.p.) was administered once on Day 4. GbE or NAC (200 mg/kg, p.o.) was administered for 3 days before and 6 days after MTX exposure. Serum alanine aminotransferase (ALT), total and direct bilirubin and hepatic malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), tumor necrosis factor- alpha (TNF-α), interleukin-1 beta (IL-1β), Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2) were assessed. Hepatic phosphorylation of IκBα, p38 MAPK, and p53 was evaluated by Western blotting. MTX significantly (P < 0.001) increased serum ALT by 120% and hepatic MDA, TNF-α, IL-1β and Bax by 127%, 386%, 163%, and 439%, respectively, while reducing GSH and Bcl-2 by 66% and 63%, relative to control. Phosphorylation of IκBα, p38 MAPK, and p53 increased by 35%, 64%, and 68%, respectively. GbE and NAC significantly (P < 0.001) attenuated these alterations, with NAC producing generally greater effects than GbE. GbE and NAC attenuated MTX-induced hepatic injury across interconnected oxidative, inflammatory, apoptotic, and signaling endpoints. NAC showed a generally stronger response under the conditions tested. These findings support further investigation of both agents as potential strategies for mitigating MTX-associated hepatotoxicity.