Morphofunctional Features of Pancreatic Islets Structure in Three Months Old Rats and Their Alteration during the Tenth Week of Experimental Type 1Diabetes Mellitus

Specific alterations of pancreatic islets in rats at the age of 3 months during the 10th week of experimental diabetes mellitus were studied using histological and submicroscopic research methods. Received data was evaluated by parametric and non-parametric statistical methods. In diabetes there were significant changes in pancreatic islets parenchyma of pancreas; nuclei altered ultrastructurally in existing B cells. Nuclei were small; they had indistinct boundaries due to perinuclear space disappearance, a large amount of condensed chromatin which comprised a significant number of small vesicles. Composition of condensed chromatin depended on the number of secretory granules in cytoplasm ? the more granules there were, the more condensed chromatin and smaller the nucleus were detected. So, streptozotocin causes irreversible changes in pancreatic islets of pancreas; their cellular composition decreases up to 21 per cent mainly due to the reduce in B cells number. In addition, the existing cells alter by improving their functional activity.