Short-chain fatty acids induce cytoskeletal and extracellular protein modifications associated with modulation of proliferation on primary culture of rat intestinal smooth muscle cells

Short-chain fatty acids are the main end products of bacterial fermentation of carbohydrates. Their role on the metabolism and biology of colonocytes is now well characterized. However, the functional consequences of their presence on intestinal smooth muscle cells remain poorly studied. We aimed to assess the effect of different short-chain fatty acids on ileal and colonic smooth muscle cells in primary culture and on A7R5 line. Butyrate (above 0.1 mM) inhibited A7R5 cell proliferation, while at low concentration (0.05 to 0.5 mM) butyrate significantly stimulated the proliferation of ileal and colonic myocytes in primary culture. An inhibition was observed at higher concentrations. Collagenous and noncollagenous protein synthesis was stimulated by butyrate. Moreover, butyrate stimulated actin and myosin expression. Thus, butyrate, which is produced by dietary fiber fermentation, may affect intestinal muscles by directly acting at the molecular level on myocytes.