Proliferation of mast cells in the smooth muscle of denervated rat jejunum.

Mast cell hyperplasia and changes in phenotypic characteristics subsequent to myenteric and extrinsic denervation of a segment of rat jejunum were studied. The myenteric plexus and extrinsic nerves were ablated by serosal application of the cationic surfactant benzyldimethyltetradecylammonium chloride. There was a four-fold increase in the number of mast cells in the smooth muscle layers 15 days after denervation. This increase was sustained for at least 90 days after treatment. No increase in mast cell number was observed in the villus-crypt axis of the jejunum. Berberine sulfate fluorescent detection of heparin-containing mast cells demonstrated that a change in mast cell phenotype occurred between 20 and 90 days after the denervation procedure. The fact that myeloperoxidase activity was the same in denervated and control tissue within 5 days of denervation demonstrates the lack of a chronic inflammatory reaction. Our results suggest that mast cells might play a role in the gut wall re-modeling processes.