Hepatoprotective effects of curcumin against hydrogen peroxide–induced oxidative liver injury in rats
TL;DR
Curcumin showed hepatoprotective effects against H₂O₂-induced oxidative liver injury through antioxidant, anti-inflammatory, anti-proliferative, and anti-apoptotic mechanisms, with the strongest overall protection was observed at 200 mg/kg.
Abstract
Oxidative stress and inflammation contribute to liver injury and chronic disease progression. Curcumin, the major bioactive compound of Curcuma longa, has antioxidant, anti-inflammatory, and hepatoprotective activities. This study aimed to evaluate the protective effects of curcumin against hydrogen peroxide-induced oxidative liver injury in Wistar albino rats. Twenty-four rats were divided into six groups: negative control, positive control, extract-only safety control, and three H₂O₂-exposed groups treated with the Curcuma longa extract at 50, 100, and 200 mg/kg. Oxidative stress was induced by 5% H₂O₂ in drinking water for 50 days. The dried Curcuma longa extract was suspended in 0.9% sterile saline and administered orally by gavage. Liver function markers, histopathology, and hepatic expression of SOD, IL-6, MYC, and Caspase-3 were assessed. H₂O₂ exposure increased ALT from 44 ± 2.0 to 1190 ± 51.1 U/L, AST from 180 ± 7.5 to 1300 ± 77.9 U/L, ALP from 60 ± 3.2 to 340 ± 18.6 U/L, and total bilirubin from 0.7 ± 0.2 to 5.0 ± 0.2 mg/dL. It also caused severe hepatic damage, including necrosis, steatotic changes, apoptosis-like alterations, and inflammatory infiltration. Gene expression analysis showed downregulation of SOD and upregulation of IL-6, MYC, and Caspase-3. Caspase-3 increased to 5.50-fold in the H₂O₂ group, confirming activation of apoptosis-related signaling. Treatment improved the biochemical and histological findings, with the strongest overall protective effect observed at 200 mg/kg. At this dose, ALT, AST, ALP, and total bilirubin decreased to 520 ± 51.1 U/L, 550 ± 77.9 U/L, 120 ± 18.6 U/L, and 2.0 ± 0.2 mg/dL, respectively. It partially restored SOD expression, reduced IL-6 and MYC expression, and decreased Caspase-3 expression to 4.10-, 2.70-, and 1.90-fold at 50, 100, and 200 mg/kg, respectively. The reductions in IL-6 and MYC did not follow a linear dose-dependent pattern. Curcumin showed hepatoprotective effects against H₂O₂-induced oxidative liver injury through antioxidant, anti-inflammatory, anti-proliferative, and anti-apoptotic mechanisms. The strongest overall protection was observed at 200 mg/kg.