Despite the wide clinical indications, methotrexate (MTX) use is limited because of serious side effects including liver toxicity. MTX was shown to cause tissue damage by mainly oxidative stress and also inflammation and apoptosis. Thus, Nebivolol (NEB) which has antioxidant and antiapoptotic properties were thought to be effective against MTX-induced injury. This study aimed to evaluate the effects of NEB on MTX-induced liver toxicity via AKT/Hypoxia-Inducible Factor 1 Alpha (HIF1α)/Endothelial Nitric Oxide Synthase (eNOS) signaling pathways. Rats were divided into three groups as control, MTX, and NEB. A single dose of MTX (20 mg/kg intraperitoneally) was given to the rats on the first day of the experiment and NEB (10 mg/kg, daily by oral gavage) was given to the treatment group for a week. At the end of the experiment, bloods were taken for aspartate transaminase (AST), alanine aminotransferase (ALT), and total bilirubin (T-BIL) analyses. Liver tissues were harvested for biochemical (total oxidant status (TOS) and total antioxidant status (TAS), genetic (PCR analyses for AKT1, eNOS, and HIF1a), and histological (Hemotoxylin-Eosin, Masson Trichome, Periodic Acid Schiff-Asien Blue, reticulin for histological, and CD3 for immunohistochemical staining) analyses. MTX increased the levels of TOS values, AST, ALT, T-BIL levels and decreased the expressions of AKT/HIF1α/eNOS. NEB treatment reversed all these changes markedly via decreasing inflammation by nitric oxid (NO) production. In conclusion, NEB treatment significantly preserves the liver by decreasing oxidant levels and inflammatory parameters through HIF1α/eNOS signaling. Due to the antioxidant properties of NEB, it can be used in other liver injury models sharing the same pathway.
Keywords: Methotrexate; eNOS; inflammation; liver; nebivolol; oxidative stress.