The Composition And Structure Alteration Of Glycosaminoglycans In Type 2 Diabetes Rat Kidney

Glycosaminoglycans (GAGs), such as Chondroitin sulfate A (CSA), Chondroitin sulfate B (CSB) or Dermatan sulfate (DS), Chondroitin sulfate C (CSC), Heparin (HP), Heparan sulfate (HS), Hyaluronic acid (HA) are a kind of important biological macromolecules largely exist in cell membrane and extracellular matrices. Differences of GAGs content, composition, molecular size and disaccharide composition have been found in many diseases,but little was referred to type 2 diabetes mellitus. Therefore, the aim of this study was by analyzing the composition and structure of GAGs in diabetes kidney to reveal the biological contribution of GAGs in the nosogenesis and progress of type 2 diabetes.Induction of type 2 diabetes mellitus in wistar rats is carried out by induction of insulin resistance with high fat chew and fructose, and afterwards injection of a small dose of streptozocin (STZ).The glycemia of diabetes rats is 25.0±2.8 mmol/L, much higher than normal rats of 4.0±0.4 mmol/L, and also higher than 11.1 mmol/L (P<0.01), which is the referrence glycemia of diabetes worldwide.GAGs are extracted by defatting with acetone-chloroform and enzyme hydrolysis with trypsin and papain, and purified by dialysis, cation exchange chromatograph and gel filtration.The total amount of GAGs is determined with carbazole method. The molecular weight is analyzed by HPGPC. Gray value integration of electrophoresis on cellulose is estabished to determin the content of GAGs constituent. Using the methods above, GAGs from normal and diabetes rat kidney are analyzed. Results show that GAGs constituents are dermatin sulfate (DS) and heparan sulfate (HS) both in normal and diabetes rat kidney. A significant increase in total amount of GAGs (P<0.05) and DS (P<0.01) is found in diabetes rat. HS shows no difference either in respect of the content or molecular size.Disaccharides are obtained from GAGs by enzyme hydrolysis then separated and quantitated by SAX-HPLC. Results show that in term of chondroitin disaccharides, none-sulfated disaccharide significantly increases in diabetes rat kidney (P<0.01) while di/tri-sulfated disaccharides decrease (P<0.05). As to heparin disaccharides, N-acetylated disaccharide significantly increases (P<0.01) while N-sulfated and O-sulfate disaccharides decrease (P<0.01, P<0.05).Above all, this study first systematically analyzed the composition and structure alteration of glycosaminoglycans in type 2 diabetes rat kidney, which could provide important information for the research on the biological contribution of GAGs in the nosogenesis and progress of type 2 diabetes.