Choline acetyltransferase and the nicotinic acetylcholine receptor AChRα7 in experimental myositis

It is not known to what extent a non-neuronal cholinergic system is involved in myositis (muscle inflammation) evoked by marked muscle overuse. Therefore, in the present study, a recently established rabbit myositis model was used and the expression patterns of ChAT and nicotinic acetylcholine receptor AChRα7 (α7nAChR) were evaluated. Immunohistochemistry and in situ hybridization were used. The model leads to myositis including occurrence of muscle fiber necrosis. It was found that the infiltrating white blood cells as well the walls of small blood vessels exhibited immunoreactivity for both ChAT and α7nAChR. There was also pronounced immunoreactivity for these in the white blood cells that had coalesced within the necrotic muscle fibers. The findings show that there is a presence of a non-neuronal cholinergic system in the situation of muscle inflammation. Cholinergic effects may be highly involved in the inflammation-modifying events that occur in muscle overuse.