Biochemical and morphological changes in human mast cells exposed to natural á,â-unsaturated lactones

VERA ME; ROJAS RUDOLPH GI; YEFI R; MARIANI ML; DE ROSAS JC; FOGAL TH; TONN CE; PIEZZI RS; PENISSI AB

Rosario, Santa Fe, Argentina,

Congreso; 10th Inter-American Congress of Electron Microscopy 2009 (CIASEM 2009) 1st Congress of the Argentine Society of Microscopy (SAMIC 2009).; 2009

Interamericano de Sociedades de Microscopía Electrónica.

The present work was designed to examine the effect of a sesquiterpene lactone isolated from Artemisia douglasiana Besser (dehydroleucodine, DhL) and a xanthanolide isolated from Xanthium cavanillesii Schouw (xanthatin, Xt) on compound 48/80- and calcium ionophore A23187-induced human mast cell degranulation, with the goal of testing the hypothesis that such molecules act as mast cell stabilizers. The human LAD-2 cell line was incubated with: 1) Buffer (basal group) or 2) compound 48/80 (mast cell secretagogue) or 3) A23187 (mast cell secretagogue) or 4) DhL+48/80 or 5) DhL+A23187 or 6) Xt+48/80 or 7) Xt+A23187. LAD-2 â-hexosaminidase release studies by ELISA, evaluation of mast cell morphology by light microscopy (toluidine blue stain), study of mast cell ultrastructure by transmission and scanning electron microscopy, dose-response and time-response curves, cell viability evaluation (tripan blue stain), and comparative studies with ketotifen (Ket), were carried out. Compound 48/80 and A23187 increased â-hexosaminidase release from LAD-2 cells and elicited evident granule ultraestructural changes. These effects were inhibited by DhL and Xt in a dose- and time- dependent manner. The present study demonstrates that DhL and Xt inhibit compound 48/80-and A23187-induced mast cell activation, acting thus as mast cell stabilizers in a human mast cell line.