Glucose-lowering effects of Daming capsule in type 1 diabetic rats and its mechanisms

Objective To study the protective effects of Daming capsule( DM) in type 1 diabetic rats. Methods Sixty-five male sprague-dawley( SD) rats were randomly divided into 5groups( 13 rats / group) : low dose group( 50 mg·kg-1·d-1),middle dose group( 100 mg·kg-1·d-1),high dose group of DM( 200 mg·kg-1·d-1),control group,and diabetes group. DM group received DM twice a day via gavage for two weeks; control group and diabetes group received equal volume of distilled water. Rats were administered with a single intraperitoneal( i. p.) injection of streptozocin( STZ) 65 mg ·kg-1after two weeks of DM. The fasting blood glucose was measured on day 3 and 7 after STZ treatment and glucose tolerance test was performed on day 30 after STZ treatment. Hematoxylin and eosin stain( HE stain) and terminal-deoxynucleotidyl transferase mediated nick end labeling( TUNEL) assay were performed on the pancreas of the rats. Results Significant increase in the fasting blood glucose and abnormal glucose tolerance were found in the STZ-treated rats compared to controls( P 0. 05). Rats treated with different doses of DM had significant decrease in the fast blood glucose( P 0. 05) and profound improvement in glucose tolerance in diabetic rats. HE stain showed that DM protected pancreatic islet against STZ damage,reflected by increase of number of pancreatic islets in diabetic rats( P 0. 05). TUNEL results showed that DM attenuated apoptosis of pancreatic β-cells compared with diabetes group. Conclusion DM decreases the fasting blood glucose level and improves glucose tolerance by at least protecting β-cells from apoptosis in type 1 diabetic rats.