Pancreatic islet protective effect of vanadium in streptozotocin-induced diabetic rats, histological, immunohistochemical and ultrastructural study
S Ahmadi1, SM Karimian2, M Sotoudeh3 & M Bahadori3
Objective: Vanadium salts have been suggested as a possible therapeutic agent for treating diabetes mellitus in the experimental models of the disease. This study was done to show the correlation between amelioration of diabetic signs and preservation of pancreatic islets in vanadyl sulphate treated streptozotocin - induced diabetic rats.
Methods: Diabetes was induced in male Wistar rats by intravenous injection of 40 milligram per kilogram streptozotocin. Diabetic animals were divided into treated and control groups. Vanadyl sulphate was added to the drinking water of the treated group at a concentration of 1 milligram per milliliter for three months while untreated diabetic rats received tap water during this period. Rats were killed at the end of the experiment and pancreata were fixed in proper fixators. Hematoxylin-Eosin stained paraffin sections were used for histological studies. Insulin immunoreactivitiy was assessed by Horseradish Peroxidase procedure. Ultrastructural studies were done on the semi-thin pancreatic sections.
Results: Vanadyl sulphate treatment led to amelioration of the diabetic symptoms along with well preservation of islets and high insulin immunoreactivity. Ultrastructural studies showed well granulation of islet cells, normal chromatin distribution and no clear sign of cell injury. In untreated diabetic rats plasma glucose and fluid intake did not return to normal levels. Islet size and number were decreased and insulin immunoreactive beta cells were scant. Diverse degrees of injury including cytoplasm vacuolation and pyknotic nuclei were found in the islet cells.
With respect to the results of this study we concluded that part of the antidiabetic effect of Vanadyl sulphate could be attributed to the islet protective effect of this compound.