Peculiarities of death and regeneration of pancreas cells at early stages of alcoholic chronic pancreatitis

Abstract

The study has been conducted on 39 white laboratory male rats which formed 5 groups: experimental occlusal pancreatitis caused by ligation of the main pancreatic duct (n = 6), experimental alcoholic pancreatitis caused by oral intake of alcohol (n = 6), against the background of an excess (n = 6) or deficiency (n = 6) of nitric oxide, as well as a control group (n = 15). This study provides the detailed description of the processes of death and regeneration in the islets of Langerhans, typical for early stages of the disease. The expression of the proliferation markers (PCNA and Neurogenin-3) has been analyzed using histological and immunohistochemical methods along with the changes of morphological structure, that led to initiation of the alcoholic chronic pancreatitis against the background of imbalance in NO-ergic regulatory system caused by an excess or deficiency of nitric oxide. It has been found that ligation of the pancreatic duct in the experiment reconstructedthe circumstances of chronic pancreatitis in rats and caused the activation of fibrosis and regeneration of endocrine and exocrine tissue. Compared with occlusion, the effects of ethanol on the pancreas also manifested in the activation of fibrogenesis, but the structural changes were negligible and could unlikely lead to advanced fibrosis and chronic pancreatitis in the future. On the other side, an imbalance of NO-system in alcoholic rats leads to disruption of the zymogens secretion in the acinar cells and dilatation of the capillary network in islets. Uneven distribution of zymogen granules may lead to their intracellular activation as evidenced by the deformation of acini and focal apoptosis without inflammatory response. In this case, violation of the key adaptive responses in the pancreas makes it more vulnerable to the effects of ethanol, its metabolites, and other environmental factors, and may increase the probability of chronic pancreatitis development. At the same time, forementioned process of cell death in the pancreas is considerably more prolonged, and long term course eliminates the activation of proliferation or functional tissue regeneration.