Effect of Juvenile Obesity on the Islets of Langerhans in Rat and the Possibility of Recovery at Adulthood: A Histological and Immunohistochemical Study

Abstract

Background: Juvenile obesity is a serious problem that increases the risk of future development of cardiovascular disease and type 2 diabetes at adulthood through programing a metabolic dysfunction during development. Aim of the Work: to perform a biochemical, histological and immunohistochemical evaluation of the effect of juvenile obesity on the morphology, insulin expression, apoptosis and proliferation of the islets of Langerhans in albino rat and to evaluate the possibility of recovery at adulthood. Material and Methods: Twenty-one juvenile male albino rats were equally divided into 3 groups; control (fed 11% fat standard diet), high fat diet-induced obesity group (fed 45% fat diet for 8 weeks) and recovery group (fed 45% fat diet for 8 weeks then left for 4 weeks on standard diet). Animals were weighed and fasting blood glucose and serum insulin were quantified. Pancreatic specimens were processed for histological and immunohistochemical staining for detection of insulin, Bcl2 and Ki67. Results: Juvenile obesity group recorded a significant increase in total body weight and blood glucose coupling with a significant decrease in serum insulin. Histological examination revealed few shrunken islets of Langerhans with cells expressing nuclear alterations and cytoplasmic vacuolation. Peripheral mononuclear infiltration and dilated congested blood capillaries were observed. A significant decrease in the immunohistochemical expression of insulin, Bcl2 and Ki67 was recorded. While a significant improvement of all studied parameters was detected in the recovery group. Conclusion: Restoration of a normal diet in high fat diet-induced obesity in juvenile rats reinstated the abnormal glucose and insulin levels, ameliorated the altered morphology of islets of Langerhans, and upregulated the suppressed immunoexpression of insulin, Bcl2 and Ki67 in the islets at adulthood.