Hypoglycemic Effect Of Chitosan-microcapsulated Insulin On The Blood Glucose Level Of Streptozotosin-diabetic Wistar Rats

Objective:(1)To observe the absorption and targeted distribution of chitosan-microcapsulated insulin(insulin-microspheres) in Wistar rats by gavage.(2)To test hypoglycemic effect in streptozotocin(STZ)-inducing diabetic rats after oral administration of insulin-microspheres .comparing with using insulin by subcutaneous injection.Methods:(1)chitosan-microcapsulated insulin(insulin-microsphere) was prepared by solvent evaporated technique, which diameter was smaller than Sum.(2)4 normal Wistar rats were sacrificed at 1,2,3,7day after given insulin-microsphere by gavage respectively, their small intestine, liver, spleen were examined using scanning electron microscope.(3)18 streptozotocin(STZ)-inducing diabetic rats were divided into three groups: diabetic control rats(group C, n=6); diabetic rats treated with insulin-microsphere[120u/kg] by gavage(group G, n=6); diabetic rats treated with insulin injection(24u NPH/kg. group I, n=6).In addition, there was one group of normal control rats(group N, n=5). Blood glucose of four groups was measured at 0-7 days.Result:(1)chitosan-microcapsulated insulin(insulin-microspheres) could be absorbed through small intestine and targeted distributed in small intestine, liver,spleen in Wistar rats. Insulin-microspheres were found in small intestine at 1,2,3 day, in liver and spleen at 2,3,7 day in normal rats after gavage. But no insulin-microspheres was found in small intestine at 7 day.(2)In group G , the average blood glucose level decreased significantly from 24.7?.2rnmol/L to 16.9?.5mmol/L in the first day of treatment and reached the lowest level(12.1 ?5.7mmol/L) in the second day. From the third day on, the blood glucose gradually elevated to the level before treatment; the maximum decreasing rate of blood glucose was 50.2%. In group I . the average blood glucose level decreased from 25.2 ?3.8mmol/L to 10.4 ?5.2mmol/L in the first day of treatment and then went up gradually from the second day on; the maximum decreasing rate of blood glucose was 58.7%. There was no significant different in maximum decreasing rate between the two groups. There was no change on blood glucose in group N and group C.Conclusion:(1)Oral chitosan-microcapsulated insulin could be absorbed through small intestine and targeted distributed in small intestine, liver, spleen and gradually degraded in Wistar rats.(2)There was the antihyperglycemic effect on the blood glucose level of streptozotocin-inducing diabetic rats by Oral administration of chitosan-microcapsulated insulin(insulin-microspheres).