Neuroimmunomodulation in the iodoacetamine-induced gastritis in rats

Background and study aims: Defense mechanisms – including immune responses – of the gastrointestinal tract are influenced by the nervous system, however no reports are available about the changes of the distribution and density of neuropeptide containing nerve fibres and their contacts with the immunocompetent cells in experimental gastritis. Therefore our aim was to investigate the precise localization and density of the nerve fibers and immunocompetent cells and their contacts in iodoacetamine-induced gastritis in rats.

Materials and Methods: substance P (SP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), galanin, and tyrosine β-hydroxylase immunoreactive (IR) nerve elements and immunocompetent cells were detected by ABC immunohistochemistry in the control and gastritis of the rats.

Results: The quantitative analysis of the density of the different neuropeptide containing nerve fibres showed that the IR nerve fibres were found with different density. The number of SP, VIP, NPY IR nerve fibres were increased significantly (P<0.05) in the gastritis, however, the others showed no significant 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 changes in the density of nerve fibres and immunocytes might be the consequences of the inflammation. The increased number of SP IR nerve fibres and SP IR immunocytes might multiply the inflammation as well as they can modify the neuro-immune processes in gastritis.