Morphology of pancreatic endocrine cells in rats with type 2 diabetes after the long-term treatment with sulphonylureas

Abstract

Aim: to study the morphology of pancreatic islet cells in rats aged more than 1 year with experimental type 2 diabetes (T2D) that receive sulphonylureas for a long time.Patients and Methods: albino laboratory rats aged more than 1 year (equal to 40 years in humans) were enrolled in this experimental study. Streptozotocin and nicotinamide were administered to induce T2D (streptozotocin-nicotinamide-induced diabetic rats). The animals were divided into four groups, i.e., healthy controls, T2D with no treatment, T2D treated with glibenclamide, and T2D treated with gliclazide. After the experimental study, immunohistochemistry with the antibodies against insulin, glucagon, and Ki-67 was performed. Morphometric analysis was performed using microphotographs. Insulin-, glucagon- and Ki-67-positive cells in islets were calculated.Results: by the 24th week of the study, the ratio of the total volume of α-cells to islet area in rats receiving glibenclamide was similar compared to diabetic rats receiving no treatment (p=0.75). Meanwhile, the significant reduction in the number of α-cells was reported in rats receiving gliclazide compared to diabetic rats receiving no treatment (p=0.000004). Moreover, the number of α-cells was equal to healthy controls. The total volume of β-cells remained unchanged in rats receiving glibenclamide or gliclazide as compared with diabetic rats with no treatment.Conclusion: our findings demonstrate that older animals (>1 year of age) are characterized by the changes in the ratio of α- and β-cells that are similar to the adults with T2D, i.e., the reduction in the percentage of β-cells and the increase in the percentage of α-cells. Long-term treatment with sulphonylureas does not result in the additional changes in the number and total volume of β-cells (rats receiving sulphonylureas for 24 weeks are similar to T2D rats with no treatment in terms of the volume of β-cells). However, 24-week treatment with gliclazide results in the normalization of the total volume of α-cells, and their number is comparable to healthy controls.KEYWORDS: sulphonylureas, α-cells, β-cells, pancreas, type 2 diabetes. FOR CITATION: Tuchina T.P., Skotnikova K.P., Vtorushina A.A. et al. Morphology of pancreatic endocrine cells in rats with type 2 diabetes after the long-term treatment with sulphonylureas. Russian Medical Inquiry. 2020;4(6):329–333. DOI: 10.32364/2587-6821-2020-4-6-329-333.