Study on regulation of NLRP3/SOCS3-TLR4-NF-κB inflammatory pathway by wogonoside to improve hepatic insulin resistance / 中国中药杂志

ABSTRACT

This study was to investigate the hypoglycemic effect of wogonoside to improve hepatic insulin resistance( IR) and its relative anti-inflammatory mechanism. The stable IR-Hep G2 cell model was established by the combination of 1×10-9 mol·L-1 insulin and 3. 75×10-6 mol·L-1 dexamethasone for 48 hours. The changes of glucose consumption in IR-Hep G2 cells with different concentrations of wogonoside( 1,5,10,20,50 μmol·L-1) at different time points( 30,36,48,54 h) were detected by glucose oxidase assay to determine the optimal onset time. Glycogen content and cell viability were respectively detected by ketone method and CCK-8 method. Cryptothermal protein 3( NLRP3),suppressor of cytokine signaling 3( SOCS3),Toll-like receptor 4( TLR4),nuclear factor( NF-κB),interleukin( IL-1β),IL-6,tumor necrosis factor( TNF-α) involving in the inflammatory signaling pathway,as well as leptin,Ob-R,p-IRS2/IRS2,p-PI3 K/PI3 K( p85),p-Akt/Akt and glucose transporter( GLUT1/2/4) involving in the insulin signaling pathway were detected in IR-HepG2 cells by Western blot. RESULTS: showed that 20 and 50 μmol·L-1 wogonoside significantly up-regulated the glucose consumption of IR-HepG2 cells( P<0. 001) as compared with IR model group,and the optimal onset time was 48 h.Wogonoside had no obvious effect on the cell viability of Hep G2 cells. Further studies showed that 20,50 μmol·L-1 wogonoside respectively increased the glycogen content of IR-HepG2 cells after 48 h treatment,especially in 50 μmol·L-1 group( P<0. 001). Compared with IR model group,wogonoside not only inhibited the protein expression of inflammatory nuclear transcriptional factors NLRP3,SOCS3,TLR4,NF-κB,but also decreased the expression of downstream inflammatory effect factors IL-1β,IL-6 and TNF-α． In addition,wogonoside elevated Ob-R,p-IRS2/IRS2,p-PI3 K/PI3 K( p85),p-Akt/Akt and GLUT1/2/4 protein expression,whereas it suppressed leptin expression that was regulated by SOCS3. Wogonoside could promote glucose uptake and increase glycogen content to enhance insulin sensitivity in IR-Hep G2 cells. The hypoglycemic effect may be related to the intervention of NLRP3/SOCS3-TLR4-NF-κB inflammatory pathway and decrease of inflammatory factor expression.