An immunohistochemical study of endocrine cells in the iodoacetamine-induced rat's gastritis

Abstract

The gastric epithelium is a complex stucture formed by tubular gastric glands. The gastric glands contain a wide variety of cell types according to the secretion of hydrochloric acid, proteases, mucus, pepsinogen and hormones. Endocrine and local paracrine mediators are of crucial importance for maintaining structural and functional integrity of the epithelium. Therefore our aim was to investigate the precise localization and density of the endocrine cells and their contacts in iodoacetamine-induced rat's gastritis. Methods: somatostatin (SOM), calcitonin gene-related peptide CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and galanin immunoreactive (IR) endocrine cells and nerve elements were detected by ABC immunohistochemistry. Results: The quantitative analysis of the density of the different neuropeptide containing endocrine cells and nerve fibres showed that the (IR) nerve fibres were found with different density. The number of SOM and CGRP IR endocrine cells increased significantly in the gastritis. Both endocrine cells possessed long cytoplasmic extensions and no cell-to-cell contact between parietal and endocrine cells was found. The number of SP, VIP, NPY IR nerve fibres also increased significantly in the gastritis, however, the others showed no alteration. The number of the immunocompetent cells was also increased (being lymphocytes, plasma cells and mast cells) and 16,8% of the immunocytes were IR for SP and 9, 4% of them were IR for NPY. In several cases close contacts were detected between IR nerve fibres and the immunocytes. Conclusions: The increased number of SOM and CGRP endocrine cells and SP IR nerve fibres might play a crucial role in the regulation of gastric acid secretion, including gastric ulcer disease and autoimmune gastritis. The main inhibitor of acid secretion is somatostatin. CGRP activates the mucin biosynthesis, both SOM and CGRP have a preventive action on gastric mucosal injury. The changes in the density of nerve fibres and immunocytes might be the consequences of the inflammation.