Objective: To investigate the preventive effect of Radix Astragali (RA) on insulin resistance caused by tumor necrosis factor-alpha (TNF-alpha).
Methods: Normal rats were pretreated with RA or distilled water by intragastric infusion for one week. Glucose-insulin tolerance test was conducted in the rats 4 h after low dose TNF-alpha injection by caudal vein to estimate the change in insulin sensitivity. Meanwhile, the plasma glucagon, ACTH, blood lipid, and glycogen, triglyceride in tissue were also observed.
Results: Exogenous TNF-alpha could induce hyperinsulinemia in normal rats. K value in glucose-insulin tolerance test decreased, serum ACTH, glucagon, blood lipid increased, glycogen content in liver and red quadriceps muscles decreased, the liver triglyceride level increased in the TNF-alpha treated rats. RA could improve all the above-mentioned changes significantly except the blood lipid and triglyceride depots in liver.
Conclusion: RA has obvious preventive effect on insulin resistance caused by TNF-alpha, it may be due to its action in decreasing insulin antagonistic hormones and increasing glycogen synthesis in tissue.