Effect of Quercetin on the Endocrine Pancreas of the Experimentally Induced Diabetes in Male Albino Rats: A Histological and Immunohistochemical Study

Abstract

Background: Insulin dependent diabetes mellitus is a chronic metabolic disease. Many drugs used in its treatment which have a number of serious adverse effects. Natural agent as quercetin (QCT) has been suggested in the alternative medicine for treatment of diabetes mellitus. Aim of the work: To evaluate the effect of QCT on the histological changes which occur in the islet of Langerhans of the streptozotocin (STZ)-induced diabetic rats and the possible mechanisms through which QCT produces its protective effect. Materials and methods: Fourty five male albino rats were divided into 3 groups: Group I, control group; 15 rats received single intraperitoneal injection of citrate buffer saline. Group II, diabetic group; 15 rats received single intraperitoneal injection of STZ. Group III; QCT-treated group, 15 rats received daily intraperitoneal injections of QCT for 30 days prior to, and for 30 days after the single injection of STZ. Blood samples were taken for monitoring blood glucose levels. Pancreas was taken out and processed for light microscopic, immunocytochemical and morphometrical studies. Results: Blood glucose levels showed a significant increase in group II compared to the control, while a significant decrease was observed in groups III compared to group II (all p<0.05). In the hematoxylin-eosin stained sections, STZ administration caused marked degeneration of islet Beta cells with inflammatory cells infiltration. Using QCT; in group III, reversed most of the pancreatic morphological changes, and interestingly some islets noticed with connections to some pancreatic ducts. In chrome alum heamatoxylin stained sections, STZ administration caused a significant decrease in the number of bluish stained β cells compared to controls. While group III showed a significant increase in β cells number compared to group II (all p<0.05). Sections of animals injected with charcoal, showed many charcoal labeled macrophages in group II compared to group III, and controls. There was increased iNOS and caspase 3 immunoreactivity in islets cells of group II than in controls, and was decreased in group III. Conclusion: This study provides evidence that quercetin could exert a protective effect against β cell damage by its anti-inflammatory, anti-apoptotic, and antioxidant effects; and aids regeneration of β cells which might through stimulation of the ductal stem cells. However, further experimental studies are still needed for more details on quercetin as an adjuvant drug in management of diabetes mellitus.