| Diabetes mellitus is a kind of metabolism disease relative to the heredity and the long-term effect of environment,mainly caused by absolutely or partly insulin secrete insufficient and/or significantly high activity of pancreas glucagon. The key to treat diabetes mellitus is how to effectively control the blood glucose level, and reduce the hypoglycemia. Research showed that the chitosan played a role of lowering blood glucose and fat and enhancing immune function obviously. Not only the modified water-soluble chitosan has the similar nature to chitosan, but also is some biological activities more remarkable and better efficiency of digestion, absorption in the intestine. In this paper, we using the method of multiple low-dose of streptozotocin (MLD-STZ) established diabetes mellitus model. To investigate the best treatment concentration of water-soluble chitosan and the mechanism of this action discussed elementarily about it.Different concentrations of water-soluble chitosan were administered to normal mice. Simultaneously, the mice's MTD (Maximal tolerance dose) test was carried on. Results indicated that water-soluble chitosan showed no evident effect in normal mice, and no toxic symptom and death phenomenon. The results elementarily displayed that water-soluble chitosan could not affect the normal mice's glucose metabolism process and were innoxious. Different concentrations of water-soluble chitosan were administered to diabetic mice, and then the levels of blood glucose, serum insulin, C- peptide and the contents of hepatic glycogen were separately calculated in normal and experimental hyperglycemias. This paper had established the diabetic mice successfully and the symptoms were similar with human type I diabetes.There was a reduction in blood glucose level in high-concentration water-soluble chitosan in week 6 with changes in blood glucose level of -39.42% as compared with diabetic mice; nevertheless the mid-concentra- tion could reduce blood glucose level but the mean was not significantly different and the low-concentration had no significant difference with diabetic mice. These experiments showed that water-soluble chitosan could obviously reduce the level of blood glucose in a concentration -dependent manner.The research of blood serum insulin and the C-peptid indicated that water-soluble chitosan could evidently increase the level of insulin and C-peptide by repairing damaged beta cell, including the normal glucose metabolism, thus play an important role in improving diabetes mellitus. Water-soluble chitosan also could increase the contents of hepatic glycogen by effectively regulating sugar content in mice.The glycogenesis indicated that water-soluble chitosan could reduce the effect on alanine as substrate. Pancreas islet beta cell HE reaction showed that water-soluble chitosan could restore the histology structure of damaged pancreas islet beta cells.In summary, the water-soluble chitosan had the better treatment function in the MLD-STZ diabetic mice, can reduce the level of blood glucose obviously, increase the content of serum insulin and C-peptide, and may also improve the general living condition of mice to resist the reducing of the body weight. However the water-soluble chitosan has no effect on blood glucose in normal mice which indicated that it does not stimulate Langerhans' island cells to release insulin directly, as long as the unusual blood glucose appears, possibly through the mechanism of promoting the island of Langerhans cells repair to enhance the insulin secretion and increase periphery organize sensitiveness to insulin to reduce the blood glucose and regulate the function of organism glucose metabolism. |
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