Histological Study of L-Arginine on the Pancreas and Liver of Adult Male Albino Rat and Possible Role of Dexamethazone

Abstract

Acute pancreatitis is an inflammatory process of the pancreas with possible peri-pancreatic tissue and multiple-organ involvement inducing multi-organ dysfunction syndrome with an increased mortality rate. Acute pancreatitis progresses with a local production of inflammatory mediators. These pancreatic mediators released to blood stream may pass through the liver before their dilution in the systemic circulation leading to the involvement of the liver in the events triggering the multi-organ dysfunction associated with acute pancreatitis. In the past year, a number of researches about the initiation and propagation of AP have been done, but to date no fully effective drug or treatment is available. The effects of glucocorticoids on AP have remained contradictory. The aim of this study was to investigate the time courses of the effects of dexamethasone on microscopical changes occurring in the pancreas and liver of rats used as models of AP induced by L-arginin. To achieve this goal, 60 adult male albino rats weighing 150-200 gm were used. They were divided into 3 groups: I. Control group: Which is also divided into 2 subgroups (a & b) each of animals of the first were IM injected with 0.5ml/100gm B.W saline and those of second were injected by 0.5mg/100gm B.W dexamethasone. II. L-Argininegroup:which received L-Arginineto induce AP.The animals of this group were divided into 3 subgroups a, b and c the animals of which were sacrificed 3 days, 2 weeks and 1 month after L-Arginineinjection respectively. III. Dexamethasone and L-Argininegroup:-in which the animals were injected with both L-Arginineand dexamethasone. They were also divided into 3 subgroups a, b and c, the animals of which were sacrificed 3 days. 2 weeks, one month after the injection of the drugs. The livers and pancreas of the sacrified animals were dissected out and prepared for microscopical examination. In the animals of AP model, the endocrinal part of pancreas (islets of Langerhans) was not affected all-through the experiment. The changes were only detected in exocrinal part of the gland and stroma. Three days after the injection of L-Arginine, the parenchyma of the exocrinal part of the gland was greatly distorted. It was formed of dispersed cells which had lost their acinar arrangement. These cells showed signs of cell death. Some small aggregates of fat cells were seen in the stroma. The collagenous fibres stroma was increased. Two weeks after L-Arginineinjection, the gland was composed mainly of stroma of loose C.T. in which widely dispersed groups of ducts were present with more intense mononuclear cellular infiltration. Large aggregates of fat cells were also seen. No other parenchymal cells or acini could be detected.