Isorhamnetin protects against D-GalN/LPS-induced acute liver injury in mice through anti-oxidative stress, anti-inflammation, and anti-apoptosis.

Abstract

Background: Acute liver injury (ALI), which can progress to cirrhosis, hepatocellular carcinoma and acute liver failure, has become a global concern and a serious threat to human life and health. Isorhamnetin (ISO) is an O-methylated flavonol from the class of flavonoids. It has a protective effect on various organs, but its effect on ALI is still unclear in current studies.

Purpose: This study aimed to investigate the protective effect of ISO against D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced ALI and to explore the underlying molecular mechanisms.

Methods: Ninety-six male Kunming mice were randomly divided into six groups and given the appropriate drug administration for 14 days. The ALI mouse model was established by intraperitoneal injection of 700 mg/kg D-GalN and 10 µg/kg LPS. Hematoxylin-eosin (HE) staining was performed to observe the histopathological changes. Enzyme-linked immunosorbent assay (ELISA) and quantitative Real-time Polymerase Chain Reaction (qRT-PCR) were performed to detect the expression of genes related to oxidative stress and inflammation. Inflammation and apoptosis related factors were detected by western blot.

Results: ISO alleviated D-GalN/LPS-induced ALI, reducing the alanine transaminase (ALT), aspartate transaminase (AST), and malondialdehyde (MDA) levels (P < 0.01), while improving histopathology (P < 0.05). Additionally, ISO elevated the superoxide dismutase (SOD) level, and improved the survival rate of mice (P < 0.01). Moreover, ISO reduced the nitric oxide (NO), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) levels (P < 0.05), while increasing the glutathione (GSH), and catalase (CAT) levels (P < 0.05). ISO also decreased the expression of nuclear factor-kappa B alpha (IκBα), Nuclear factor kappa-B (NF-κB) p65, IL-1β, IL-6, TNF-α, nitric oxide synthase (iNOS), and toll-like receptor 4 (TLR4) at the messenger ribonucleic acid (mRNA) level (P < 0.05). Furthermore, western blot showed that ISO decreased the expression of NF-κB p-p65, cysteine aspartate protease-3 (caspase-3), and B-cell lymphoma 2-associated X protein (Bax) proteins and elevated the expression of B-cell lymphoma 2 (Bcl-2) and B-cell lymphoma 2-like protein (Bcl-xL) proteins (P < 0.05).

Conclusions: ISO could alleviate D-GalN/LPS-induced ALI by attenuating oxidative stress and inflammatory cytokines, enhancing the expression of anti-apoptotic proteins, reducing hepatocyte apoptosis, and inhibiting the activation of the NF-κB signaling pathway. Our study will provide some new references for treating ALI with ISO.