Does the Rheumatoid Arthritis Affect the Enteric Nervous System?

Abstract

Background -Few studies regarding arthritic diseases have been performed to verify the presence of the neurodegeneration. Given the increased oxidative stress and extra-articular effects of the rheumatoid arthritis, the gastrointestinal studies should be further investigated aiming a better understanding of the systemic effects the disease on enteric nervous system. Objective -To determine whether the rheumatoid arthritis affects the nitrergic density and somatic area of the nNOS-immunoreactive (IR) myenteric neurons, as well as the morphometric areas of CGRP and VIP-IR varicosities of the ileum of arthritic rats. Methods -Twenty 58-day-old male Holtzmann rats were distributed in two groups: control and arthritic. The arthritic group received a single injection of the Freund's Complete Adjuvant in order to induce arthritis model. The whole-mount preparations of ileum were processed for immunohistochemistry to VIP, CGRP and nNOS. Quantification was used for the nitrergic neurons and morphometric analyses were performed for the three markers. Results -The arthritic disease induced a reduction 6% in ileal area compared to control group. No significant differences were observed in nitrergic density comparing both groups. However, arthritic group yielded a reduction of the nitrergic neuronal somatic area and VIP-IR varicosity areas. However, an increase of varicosity CGRP-IR areas was also observed. Conclusion -Despite arthritis resulted in no alterations in the number of nitrergic neurons, the retraction of ileal area and reduction of nitrergic somatic and VIP-IR varicosity areas may suggest a negative impact the disease on the ENS. HEADINGS -Rheumatoid arthritis. Enteric nervous system. Freund's adjuvant. Rats. Nitrergic neurons.