MORPHOLOGICAL AND IMMUNOHISTOCHEMICAL CHARACTERISTICS OF THE PANCREAS IN RATS UNDER ADRENALINE-INDUCED STRESS

This study presents the results of morphological, morphometric, and immunohistochemical investigations of the pancreas in rats subjected to adrenaline-induced stress. It was established that prolonged administration of adrenaline causes biphasic structural and functional changes: at the early stages, compensatory-adaptive reactions predominate (hypertrophy of endocrine cells, hyperplasia of the islets of Langerhans, and increased expression of BCL-6 and Ki-67), whereas at later stages, dystrophic and atrophic processes develop in the exocrine parenchyma. Immunohistochemical analysis revealed a significant increase in the expression of the anti-apoptotic regulation marker BCL-6 (from 12.3 ± 1.4% to 42.4 ± 6.1%; p < 0.001) and the proliferation marker Ki-67 (from 10.1 ± 1.2% to 36.72 ± 4.15%; p < 0.001) in endocrine cells. Morphometric analysis confirmed a significant increase in nuclear volume by 0.59-fold, cytoplasmic volume by 0.66-fold, total cellular volume by 0.64-fold, and the nuclear-to-cytoplasmic ratio by 0.88-fold in the endocrine cells of the experimental group.