ABSTRACT
This study aimed to explore the impacts of Cyclocarya paliurus polysaccharide (CP) on insulin signal pathway in liver cells.H4IIE liver cells of rat that cultivated for 72 h were made up for the model group.H4IIE cells at 70％-80％ confluence were exposed to various concentrations of CP,including 50,100,200 and 400 μg·mL 1,for measuring cell viability using Neutral Red.Based on the results of cell viability,H4IIE cells were divided into the control group,the insulin group (100 nmol·L-1),the low dose CP group (the LCP group,200 μg· mL-1) and the high dose CP group (the HCP group,400 μg· mL-1).After the cultivation of cells for 2 h,mRNA levels were measured by real-time RT-PCR,while phosphorylation levels of target proteins were detected by western blot after the treatment for 30 min.It was found that the cell viability indexes in the cells administered by 100,200 and 400 μg·mL-1 CP increased significantly compared with the control group (P＜0.01).After the administration for 2 h,InsR and IRS-2 mRNA expressions in the insulin group,the LCP group and the HCP group increased (P＜0.05 or P＜0.01).After the administration for 30 min,phosphorylation levels of InsRβ,IRS-2 and Akt in the insulin group were higher than those in the HCP group (P＜0.01).In conclusion,CP probably increased the cell viability of H4IIE cells,and improved the blood glucose index through enhancing the mRNA expressions of InsR and IRS-2 and the phosphorylation levels of InsRβ,IRS-2 and Akt in the liver.