Kaempferol Ameliorated Alcoholic Hepatitis through Improving Intestinal Barrier Function by Targeting miRNA-155 Signaling.

Introduction: The aim of this study was to investigate the effect and mechanism of kaempferol on alcoholic steatohepatitis.

Methods: C57BL/6 N mice were utilized to establish Binge-on-Chronic alcohol exposure mice model. Kaempferol was given as the interventional drug to chronic alcohol-fed mice for 6 weeks to assess its effects. In vitro, intestinal epithelial Caco-2 cells were stimulated by alcohol, and miRNA-155 mimics were used to further study the effect of kaempferol to miRNA-155 signaling in intestinal epithelial cells. HE staining and oil red O staining were used to observe the liver and intestinal tissue damage in each group of mice, and ALT, AST, IL-1β, and TNF-α were detected by kits; lipopolysaccharide (LPS) expression was detected by ELISA kit, and the expression of IL-1β and TNF-α was assessed by qRT-PCR; Western blot was utilized to assess the excessive inflammatory response of liver and colon tissue and the related signaling pathway activation.

Results: Kaempferol treatment significantly improved pathological changes such as steatosis and vacuolated lesions in liver tissue of the alcohol diet model group, and reduced serum ALT and AST enzyme activities and liver tissue interleukin-1β and tumor necrosis factor-α mRNA expression levels. Kaempferol significantly reduced the expression of miRNA-155 in the intestinal tissue of alcohol-fed mice, significantly increased their cytokine suppressor signaling 1 (SOCS1) protein expression, inhibited the activation of nuclear factor kappa-B and significantly increased the production of the intestinal tight junction proteins occludin and zonula occludens-1. More importantly, kaempferol significantly reduced serum LPS levels in alcoholic steatohepatitis mice. In vitro experiments showed that compared with the control group, kaempferol significantly inhibited the expression level of miRNA-155 in Caco-2 cells under ethanol exposure, decreased the activation of nuclear factor kappa-B, led to an increase in the expression of SOCS1 protein, and increased the production level of occludin protein in Caco-2 cells under the effect of alcohol. In contrast, overexpression of miRNA-155 significantly decreased occludin and SOCS1 protein production and increased nuclear factor kappa-B activation levels in Caco-2 cells, and the administration of kaempferol significantly inhibited this effect.

Conclusion: Kaempferol improved the stability of gut barrier function to ameliorate hepatic injury induced by alcohol intake through enhancing occludin protein expression, by targeting miR-155 to inhibit the excessive inflammatory response in the intestine.