IDF21-0217 Sialidase and sialyltransferase activities are modulated in some organs of type 1 and type 2 diabetic rats

Abstract

Background: Diabetes mellitus leads to an aberrant metabolism of sialoglycoconjugates. One of the main features of the pathophysiology of diabetes is elevated serum level of free sialic acids. The source of serum free sialic acid during diabetes is debatable, although the contribution of endothelial damage has been recognised. Aim: The aim of this study is to investigate the association between the level of sialic acids and activities of sialidase and sialyltranferase in the serum and some diabetes-related organs in animal model of type 1 (T1D) and type 2 (T2D) diabetes. Method: Both types of diabetes induced in albino rats using high and low dose streptozotocin respectively. The level of sialic acid and activities of sialidase and sialyltransferase were measured in the serum, liver, pancreas, skeletal muscle and kidney of the diabetic rats and matching controls at early (3rd week) and late (9th week) phases of the diseases. Results: Serum sialic acid level and sialidase activity were significantly elevated at late stage of both T1D and T2D. The activity of sialyltransferase was not significantly changed in the diabetic animals compared to the non-diabetic controls. The total sialic acid content of the pancreas and kidney significantly increased from the early phase of both T1D and T2D to the late phase. On the other hand, the sialic acid content of the liver significantly decreased in the early phase of T2D and the late phase of T1D.The sialic acid content of the skeletal muscle significantly increased in the late phase of both diabetes types. In the early phase of both T1D and T2D, sialidase activity significantly increased in most of the organs whereas sialyltransfease activity was unchanged. A multiple regression analysis revealed the contribution of the liver to the serum level of sialic acid and the contribution of the pancreas and kidney to the serum activity of sialidase. Discussion: It was concluded that the released of sialic acid from the liver and sialidase from the pancreas and kidney may contribute to the increased serum level of sialic acid during diabetes.