Antidiabetic effects of chitosan oligosaccharides in neonatal streptozotocin-induced noninsulin-dependent diabetes mellitus in rats

The antidiabetic effect of chitosan oligosaccharide (COS) was investigated in neonatal streptozotocin (STZ)-induced noninsulin-dependent diabetes mellitus rats. The fasting glucose level was reduced by about 19% in diabetic rats after treatment with 0.3% COS. Glucose tolerance was lower in the diabetic group compared with the normal group. After diabetic rats had been treated with 0.3% COS for 4 weeks, glucose tolerance increased significantly versus the diabetic control group, and glucose-inducible insulin expression increased significantly. In addition, fed-triglyceride (TG) levels in diabetic rats drinking 0.3% COS were reduced by 49% compared with those in diabetic control rats. The cholesterol levels of animals treated with COS were reduced by about 10% in fed or fasting conditions versus the corresponding controls, although the difference was not statistically significant. It was found that COS has a TG-lowering effect in diabetic rats, and that COS reduces signs of diabetic cardiomyopathy such as vacuolation of mitochondria and the separation and degeneration of myofibrils. In conclusion, these results indicate that COS can be used as an antidiabetic agent because it increases glucose tolerance and insulin secretion and decreases TG.