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

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.

Jatrorrhizine regulates GLUTs with multiple manners for hypoglycemic effect in insulin-resistance 3T3-L1 adipocytes / 中国中药杂志

This paper aimed to investigate the hypoglycemic effect and relative mechanism of jatrorrhizine in insulin-resistance (IR)-3T3-L1 adipocytes. The 3T3-L1 preadipocytes were used to induce mature adipocytes, then the stable IR model was established with 1 μmol·L⁻¹ dexamethasone. The adipocytes were divided into normal group, IR model group, rosiglitazone positive group and jatrorrhizine group (0.5, 1, 5, 10, 20 μmol·L⁻¹). After different time points (12, 24, 30, 36, 48 h) treatment, glucose content of 3T3-L1 adipocytes was detected by the glucose oxidase peroxidase method and TG content was measured by glycerol phosphate oxidase method, whereas cell viability was detected by CCK-8 assay. Furthermore, the protein expression levels of insulin receptor substrate 2 (IRS2), phosphinositide-3-kinase regulatory subunit 1(PI3KR1), phosphorylated protein B [p-AKT (Ser473)], phosph-AMP-activated protein [p-AMPK (Thr172)], and glucose transporter type 4/1/2 (GLUT4/1/2) were detected by Western blot assay. The results showed that as compared with the normal group, the glucose consumptionwas significantly decreased in IR model group(<0.01); whereas 0.5, 1, 5, 10, 20 μmol·L⁻¹ jatrorrhizine and rosiglitazone group elevated IR-3T3-L1 cells glucose consumption (<0.01) at 36 h and 48 h administration as compared with IR group. The optimal administration time was 48 h for jatrorrhizine. 1, 5, 10, 20 μmol·L⁻¹ of jatrorrhizine decreased the TG content in 3T3-L1 adipocytes for 48 h administration (<0.05). The protein expression levels of IRS2, PI3KR1, p-AKT (Ser473), p-AMPK (Thr172), GLUT4/1/2 were significantly up-regulated by different concentrations of jatrorrhizine and rosiglitazone (<0.01). The results showed that jatrorrhizine increased glucose uptake with elevated glucose consumption, whereas reduced intracellular TG content in IR-3T3-L1 adipocytes. Moreover, it intervened classic insulin signal pathway IRS2/PI3KR1/p-AKT/GLUT4 and increase AMPK protein phosphorylation level for the activation of GLUT1/4 for insulin sensibility. Thus, jatrorrhizine could effectively regulate the GLUTs with multiple manners for hypoglycemic effect.

Differentiated hypoglycemic effects of baicalin, berberine and puerarin on insulin-resistance HepG2 cells / 中国中药杂志

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.

Gegen Qinlian decoction activates PPARγ to ameliorate adipocytic insulin resistance in diabetic SD rats and IR-3T3-L1 adipocytes / 中国中药杂志

To investigate the effects of Gegen Qinlian decoction(GQD) in improving adipocytic insulin resistance(IR) and explore its related molecular mechanism. Diabetic rats models were induced by high glucose and high-fat diet with a small dose of streptozotocin, and after GQD treatment for 3 months, blood biochemical indexes such as fasting blood-glucose(FBG), insulin, glycosylated serum protein(GSP) and HOMA-IRI were detected and assessed. After the total RNA was extracted from the adipose tissue of diabetic SD rats, PPARγ, ADPN, GLUT4, GLUT2, ACACA and ACACB mRNA expression levels were separately detected by qPCR. Then, stable IR-3T3-L1 adipocyte model was built with 1 μmol•L⁻¹ dexamethasone. After the cell viability was detected by CCK-8 assay, 5%, 10% and 15% GQD-containing serum(GQD-CS) were respectively used to treat IR-3T-L1 adipocytes for 24 h. The contents of glucose, nonesterified fatty acid(NEFA) and adiponectin in cell culture supernatants were separately detected whereas the intracellular triglyceride(TG) contents of IR-3T3-L1 adipocytes were also measured. The ADPN, PPARγ and GLUT4 mRNA and protein expression levels were respectively detected by qPCR and Western blot in IR-3T3-L1 adipocytes. Results showed that GQD significantly decreased fasting blood glucose, insulin and GSP(P<0.01), and down-regulated HOMA-IRI(P<0.05) after the high-fat diet/streptozotocin-induced diabetic SD rats were treated for three months, with a good hypoglycemic effect. Moreover, PPARγ, ADPN, GLUT4, GLUT2, ACACA and ACACB mRNA expression levels were significantly elevated in the adipose tissue of GQD-treated diabetic SD rats. The 5%, 10% and 15% GQD-CS significantly increased glucose consumption of IR-3T3-L1 adipocytes at 24 h treatment(P<0.01), significantly decreased the intracellular TG content (P<0.01), and down-regulated NEFA to a certain extent but not significantly. Moreover, GQD-CS significantly up-regulated GLUT4 and ADPN expression. The results indicated that GQD could activate PPARγ to ameliorate adipocytic insulin resistance in the diabetic SD rats and IR-3T3-L1 adipocytes.