The α9α10 nicotinic acetylcholine receptors antagonist α-conotoxin RgIA reverses colitis signs in murine dextran sodium sulfate model

Abstract

Nicotinic acetylcholine receptors can regulate inflammation primarily through the vagus nerve via the cholinergic anti-inflammatory pathway. α9α10 nicotinic receptors (nAChRs) are a new promising target for chronic pain and inflammation. Recently, α9α10 selective α-conotoxin antagonists were shown to have antinociception effect in neuropathic and tonic inflammatory pain animal models. However, limited data available on the role of α9α10 nAChRs in experimental colitis. In this study, we report for the first time, the role of α9α10 nAChRs in the dextran sodium sulfate (DSS) experimental animal colitis model. We determined the effect of the α9α10 nAChRs antagonist, α-conotoxin RgIA (α-RgIA) in DSS-induced colitis model in adult male and female C57BL/6 J mice. DSS solution was freely given in the drinking water for seven consecutive days, and tap water was given on the 8th day. We then sacrificed mice on day 8 to examine the entire colon. Disease severity, colon tissue histology, and tumor necrosis factor-α (TNF-α) were evaluated. The lower doses (0.02 and 0.1 nmol/mouse, s.c.) of α-RgIA treatment in DSS-treated mice were inactive, whereas the higher dose (0.2 nmol/mouse, s.c.) reversed the disease activity index (DAI) score, loss of body weight, total histological damage score, as well as the colonic level of TNF-α compared to the DSS-control group. Moreover, the highest dose of α-RgIA (0.2 nmol/mouse, s.c.) significantly rescued the colon length shortening in DSS-treated mice compared to the DSS-control mice. The availability of α9*-selective conotoxins has opened new avenues in pharmacology research and potential targets in inflammatory disorders.