Apigenin attenuates hepatocyte senescence in metabolic dysfunction-associated steatotic liver disease by targeting...

This study aimed to investigate whether the natural flavonoid apigenin attenuates hepatocyte senescence and ameliorates high-fat diet (HFD)-induced metabolic dysfunction-associated steatotic liver disease (MASLD) by inhibiting the transforming growth factor-β (TGF-β)/Smad signaling pathway. Both in vivo and in vitro experiments were conducted. In vivo, an HFD-induced MASLD model was established in C57BL/6J mice, which were then treated with apigenin. Hepatic steatosis, inflammation, and fibrosis were assessed by histopathological staining, and the expression of hepatocyte senescence markers (p16, p21, and γH2AX) and key proteins of the TGF-β/Smad pathway were detected by western blotting, immunohistochemistry, and immunofluorescence. Serum lipid metabolism and indicators of liver injury were evaluated using biochemical methods. In vitro, senescence was induced in AML12 mouse hepatocytes with palmitic acid (PA), and the cells were treated with apigenin; anti-senescence effects and TGF-β pathway inhibition were confirmed by senescence-associated β-galactosidase (SA-β-gal) staining and western blotting. In the HFD-induced mouse model, apigenin alleviated hepatic steatosis, inflammation, and fibrosis, and reduced serum levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). It also decreased senescence markers (p16, p21, and γH2AX) in liver tissues and inhibited TGF-β expression and Smad2/3 phosphorylation. In the PA-treated AML12 cells, apigenin lowered senescence-associated proteins and SA-β-gal-positive cells while suppressing TGF-β/Smad pathway activation. Overexpression of TGF-β partially reversed the anti-senescence effect of apigenin, whereas pharmacological inhibition of TGF-β receptor I with SB431542 further reduced senescence markers and lipid accumulation. These findings indicate that apigenin may mitigate HFD/PA-induced hepatocyte senescence and MASLD-related pathological changes by inhibiting the TGF-β/Smad signaling pathway, offering new insights into its hepatoprotective effects.