[Study on regulation of NLRP3/SOCS3-TLR4-NF-κB inflammatory pathway by wogonoside to improve hepatic insulin resistance].

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-1ß),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-1ß,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.

[Differentiated hypoglycemic effects of baicalin, berberine and puerarin on insulin-resistance HepG2 cells].

To investigate the hypoglycemic effects of baicalin, berberine, puerarin and liquiritin on the insulin resistance (IR) cells. The IR model of HepG2 cells was established by treatment with insulin and dexamethasone for 48 h. Glucose uptake, glycogen content and cell viability were detected with different concentrations of baicalin, berberine, puerarin, liquiritin in IR-HepG2 cells. Compared with IR model group, all of intervened groups significantly increased the glucose consumption, except for liquiritin groups and 1 µmol·L⁻¹ baicalin group. Moreover, 10, 20, 50 µmol·L⁻¹ baicalin, 5, 10, 20, 50 µmol·L⁻¹ berberine and 40, 80, 160 µmol·L⁻¹ puerarin significantly elevated glycogen content in IR-HepG2 cells. Liquiritin did not show obvious hypoglycemic effect. Compared with normal group, the mRNA expression levels of GLUT1 and GLUT4 were decreased in IR-HepG2 cells according to qPCR results. 5, 20 µmol·L⁻¹ berberine decreased the mRNA expression level of GLUT1 in IR-HepG2 cells, whereas 20, 40, 80 µmol·L⁻¹ puerarin significantly elevated the mRNA expression level of GLUT1. Moreover, 10, 20, 50 µmol·L⁻¹ baicalin and 20 µmol·L⁻¹ berberine increased the mRNA expression level of GLUT4. Whereas, 40, 80 µmol·L⁻¹ puerarin decreased the mRNA expression level of GLUT4. Western blot results suggested that 10, 20, 50 µmol·L⁻¹ baicalin significantly increased the protein expressions of GLUT2 and GLUT4, whereas 20, 40, 80 µmol·L⁻¹ puerarin significantly up-regulated GLUT1 and GLUT2 proteins. In addition, 20 µmol·L⁻¹ berberine increased the protein expressions of GLUT2 and GLUT4, whereas 10 µmol·L⁻¹ berberine up-regulated GLUT4 expression. The results preliminarily suggested that baicalin, berberine and puerarin have differentiated hypoglycemic effects, which accelerate glucose transport, increase glycogen synthesis, regulate glucose metabolism and improve hepatic IR.