| Objective:IR-Hep G2 cell model was induced with high glucose and high insulin in combination. By observing the effects of different concentratins of LBP on insulin resistance in Hep G2 cells to explore the possible mechanism to improve insulin resistance, which can provides the theory basis for the further understanding and utilization of LBP,also to provide a scientific evidence for LBP treatment of type 2diabetes mellitus in clinical application.Method: IR-Hep G2 cell model was induced with high glucose and high insulin in combination for 24 hours. To identify the sucession of IR-Hep G2 model, the glucose consumption were detected. The MTT method was applied to investigate the effects of different concentrations of LBP on the activity in Hep G2 cell and to identify three suitable concentrations and time for subsequent experiments. The glucose oxidase-peroxidase method was applied to investigate the effects of different concentrations of LBP on the glucose consumption in IRHep G2 cell. Colorimetry method was applied to determine the content of malondialdehyde(MDA) and the activity of superoxide dismutase(SOD); Western-blot method was applied to detected the levels of protein expression association with insulin signaling pathway(IRS-2,PI3 K, Akt, GLUT2).Results:1.The effect of LBP on the activity of Hep G2 cells: LBP treated Hep G2 cells 24 h and 48 h, low concentration(100,300μg/ml) LBP didn’t affect the activity of Hep G2 cell; high concentrations(500,1000,3000,5000μg/ml) LBP inhibit the activity of Hep G2 cell in a concentration-dependent manner. Compared with control group(24h,0μg/ml), when the processing time is extended to 72 h, high concentration LBP inhibit the activity of Hep G2 cell more obvious in a concentration-dependent manner(P<0.05). Therefore, in order to exclude the impact of LBP on the activity of Hep G2 cell, this experiment choose 30μg/ml, 100μg/ml, 300μg/ml respectively as the concentration value of low concentration LBP group(L-LBP), middle concentration LBP(M-LBP) and high concentration LBP(H-LBP), LBP treated Hep G2 cells 48 hours.2.The effect of LBP on glucose consumption in IR-Hep G2 cells: Compared with control group, the glucose consumption of IR-Hep G2 cells was decreased significantly(P<0.05),this shows that the model of IR- Hep G2 was established successfully. Compared with IR group, high concentration and medium concentration of LBP can significantly increase the glucose consumption of IR-Hep G2 cells(P<0.05), but low concentration of LBP has no significant effect on glucose consumption in IR-Hep G2 cells(P > 0.05). Compared with rosiglitazone group, the glucose consumption of high concentration and low concentration LBP grops was significantly decreased(P<0.05), the glucose consumption of middle concentration LBP had no significantly difference(P>0.05).3.The effect of LBP on the content of MDA and activity of SOD in IR-Hep G2 cells: Compared with control group, the content of MDA was significantly increased and the activity of SOD was significantly decreased(P<0.05) in IR-Hep G2 cells. Compared with IR group, high concentration and medium concentration of LBP significantly decreased the content of MDA in insulin-resistant Hep G2 cells, but low concentration of LBP has no significantly effect on the content of MDA(P>0.05). High 、medium and low concentration of LBP all significantly increased the activity of SOD in IR-Hep G2 cells(P<0.05). Compared with rosiglitazone group, the content of MDA in middle concentration LBP group was significantly decreased(P<0.05), the activity of SOD in high and middle concentration LBP group was significantly increased(P<0.05).4.The effect of LBP on the expression of IRS-2、PI3K、Akt and GLUT2 in IR-Hep G2 cells:Compared with control group, the expression of IRS-2、PI3K Akt and GLUT2 in IR group were significantly decreased. Compared with IR group, the expressions of IRS-2、PI3K、Akt and GLUT2 of high and medium concentration LBP groups was significantly increase in IR-Hep G2 cells(P<0.05), low concentration of LBP has no significantly difference(P<0.05). Compared with rosiglitazone group, the expression of IRS-2、PI3K、Akt and GLUT2 in high 、medium and low concentration LBP groups was significantly decreased(P<0.05).Conclusions: LBP can improve insulin resistant in IR-Hep G2 cells, its mechanisms may be associated with enhancing cellular’s antioxidant capacity and increased the expression of related protein(IRS-2、PI3K、Akt 、GLUT2) in insulin-related signaling pathway. |
