histological and immunohistochemical study of pancreatic islet beta cells of diabetic rats treated with oral vanadyl sulphate

vanadium salts have been suggested as a possible therapeutic agent for the treatment of diabetes. the aim of the present study was to clarify histological and immunohistochemical changes that occur in the pancreatic beta (β) cells of vanadyl sulphate (vs)-treated streptozotocin (stz) induced diabetic rats. male wi star rats were made diabetic by injecting a single intravenous dose of stz (40 mg/kg) and were divided into two groups seven days after stz injection. in the first group vs was administered via drinking water at a concentration of 1 mg/ml and treatment was maintained until normoglycemia appeared (dt). a second group of diabetic animals received distilled water for the same period and were considered as control diabetic (dc). one group of animals (nc) was injected intravenously with the same amount of vehicle as the diabetic rats and was considered as non-diabetic control. vs treatment was accompanied by amelioration of the signs of diabetes in dt rats while dc animals remained diabetic during this period. hemotoxylin - eosin stained pancreatic sections of dc rats showed a decrease in the number and size of islets and a disruption in their architecture. in dt rats the histological appearance of the islets was normal, their shape and size being within normal limits. in horseradish peroxidase procedure (using guinea pig antiserum to insulin as primary antibody) performed on pancreatic islet paraffin sections of rats, insulin immunoreactivity was found in the majority of the islets in dt rats while in the islets of dc rats immunoreactivity was rare. the results of this study indicated that amelioration of diabetes in vanadyl sulphate treated diabetic rats was accompanied with well preservation of islet structure and insulin immunoreactivity.