PROLIFERATION OF MAST-CELLS IN THE SMOOTH-MUSCLE OF DENERVATED RAT JEJUNUM

Mast cell hyperplasia and changes in phenotypic characteristics subseq uent to myenteric and extrinsic denervation of a segment of rat jejunu m were studied. The myenteric plexus and extrinsic nerves were ablated by serosal application of the cationic surfactant benzyldimethyltetra decylammonium chloride. There was a four-fold increase in the number o f mast cells in the smooth muscle layers lj days after denervation. Th is increase was sustained for at least 90 days after treatment. No inc rease in mast cell number was observed in the villus-crypt axis of the jejunum. Berberine sulfate fluorescent detection of heparin-containin g mast cells demonstrated that a change in mast cell phenotype occurre d between 20 and 90 days after the denervation procedure. The fact tha t myeloperoxidase activity was the same in denervated and control tiss ue within 5 days of denervation demonstrates the lack of a chronic inf lammatory reaction. Our results suggest that mast cells might play a r ole in the gut wall re-modeling processes.