Kinetics and staining properties of mast cells proliferating in rat small intestine tunica muscularis and subserosa following infection with Nippostrongylus brasiliensis.

Mucosal mast-cell hyperplasia occurs in the rat small intestine mucosa after infection with Nippostrongylus brasiliensis. In the present study, the number of mast cells was found to increase in the muscularis and subserosa as well as in the mucosa of rat small intestines 2-3 weeks after infection with this nematode. Mast cells in the muscularis were stained blue by the alcian blue/safranin sequence and did not bind berberine sulfate. The staining was blocked when tissues were fixed in neutral formalin. The increase in mast cells was transient and gradually disappeared; the half-life was 40 days. After an intravenous administration of compound 48/80, mast cells in the muscularis did not discharge granules. The results indicate that these mast cells were of the mucosal type. The mast cell phenotype in the muscularis did not change even 12 weeks after infection. Mast cells in the subserosal tissue were first of the mucosal type as were those in muscularis. After 8-12 weeks, however, many subserosal mast cells became positive for berberine sulfate and safranin. These results show that mucosal-type mast cells do not undergo phenotypic changes during the period of observation when these cells appear in the muscularis but the phenotypic expression may change as the cells arise in subserosal tissue.