ABSTRACT
BACKGROUND: Capillarization of hepatic sinusoids is an inevitable part in liver fibrosis and cirrhosis, and is a characteristic lesion inducing portal hypertension. However, curcumin effects on the capillarization of hepatic sinusoids and the underlying mechanism remain unclear. OBJECTIVE: To observe the effect of curcumin (a natural polyphenolic compound derived from the rhizome of Curcuma longa)on the microstructure and secretion of hepatic sinusoidal endothelial cells(HSECs),and to further explore its intervention on sinusoidal capillarization and pharmacological action mechanism of anti-liver fibrosis and target sites. METHODS: The rat HSECs were cultured and divided into seven groups: blank control group received no intervention and cells in the other groups were activated by leptin, followed by treatment with nothing (model group), high-, medium- and low-dose of curcumin, colchicine and salvia miltiorrhiza phenolic acid B, respectively, for 48 hours. RESULTS AND CONCLUSION: Under scanning and transmission electron microscopes, with the increasing activation of leptin, the number of fenestrae in HSECs was increased and the aperture was decreased. Curcumin could increase and enlarge narrowed or disappeared fenestrae caused by leptin, attenuated the thickness and scope of extracellular basement membrane, and reduced the degree of capillarization of hepatic sinusoids in a dose-dependent manner. Real-time PCR and ELISA results showed that after activation of leptin, mRNA and protein expression levels of endothelin-1 and vascular endothelial growth factor in HSECs were significantly increased compared with the blank control group (P < 0.05), while the expressions showed a significant decrease after treatment with curcumin in a dose-dependent manner (P < 0.05). There was also a gradient reduction in the protein expression of endothelin-1 and vascular endothelial growth factor in HSECs treated with curcumin. Moreover, all above mRNA and protein expression levels in the high-dose curcumin group were significantly lower than those in the colchicine and salvia miltiorrhiza phenolic acid B groups. In summary, curcumin can significantly alleviate the sinusoidal capillarization, and thus delay the development of liver fibrosis, probably by down-regulating the expression levels of endothelin-1 and vascular endothelial growth factor.