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Background/Aims: Our previous studies have shown that plumbagin effectively inhibits hepatic stellate cell (HSC) proliferation. Thus, plumbagin-mediated anti-fibrotic effects in vivo merit further investigation. Methods: We used rat models to assess the potential benefits of plumbagin against CCl4-induced liver fibrosis. Results: The results showed that plumbagin lowered the serum concentrations of liver functional enzymes (ALT, AST, ALB, TBIL) in CCl4-fibrotic rats while reducing inflammatory cytokine levels (IL-6, TNF-a). As reflected in pathological examinations, rats that were administered plumbagin showed decreased collagen markers (HA, LN, PCIII and CIV) in liver tissues and improved hepatocellular impairments. In addition, plumbagin contributed to down-regulating NF-κB and TLR-4 mRNA in CCl4-lesioned livers. As revealed in the immunohistochemical assay, plumbagin-administered rats showed reduced levels of a-SMA and TNF-a immunoreactive cells in liver tissue. Conclusion: Collectively, these findings offer appealing evidence that plumbagin may serve as an anti-fibrotic medication through inactivating the NF-κB/TLR-4 pathway that is associated with inflammatory reactions, thereby mitigating liver fibrosis.

Critical roles for liver sinusoidal endothelial cells (LSECs) in liver fibrosis have been demonstrated, while little is known regarding the underlying molecular mechanisms of drugs delivered to the LSECs. Our previous study revealed that plumbagin plays an antifibrotic role in liver fibrosis. In this study, we investigated whether plumbagin alleviates capillarization of hepatic sinusoids by downregulating endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), laminin (LN), and type IV collagen on leptin-stimulated LSECs. We found that normal LSECs had mostly open fenestrae and no organized basement membrane. Leptin-stimulated LSECs showed the formation of a continuous basement membrane with few open fenestrae, which were the features of capillarization. Expression of ET-1, VEGF, LN, and type IV collagen was enhanced in leptin-stimulated LSECs. Plumbagin was used to treat leptin-stimulated LSECs. The sizes and numbers of open fenestrae were markedly decreased, and no basement membrane production was found after plumbagin administration. Plumbagin decreased the levels of ET-1, VEGF, LN, and type IV collagen in leptin-stimulated LSECs. Plumbagin promoted downregulation of ET-1, VEGF, LN, and type IV collagen mRNA. Altogether, our data reveal that plumbagin reverses capillarization of hepatic sinusoids by downregulation of ET-1, VEGF, LN, and type IV collagen.

To investigate the effect of plumbagin on the expression of TNF-alpha and PDGF-BB in human hepatic stellate cells (HSC-LX2) activated by Leptin.HSC-LX2 were cultured in vitro and stimulated by Leptin for 24 hours then treated with different concentrations of plumbagin for 24 hours, the expressions of TNF-alpha mRNA and PDGF-BB mRNA were determined by Realtime quantitative PCR, the protein expressions of TNF-alpha and PDGF-BB were determined-by Western blotting.The expressions of TNF-alpha mRNA and PDGF-BB mRNA of treatment groups were significantly reduced, especially in high dose group (P0.01), and Western blotting analyses revealed similar trends in protein expression.Plumbagin may prevent the formation of hepatic fibrosis and its mechanism may be related to decreasing the level of mRNA of TNF-alpha and PDGF-BB and the protein of PDGF-BB.