Imidacloprid inhibits IgE-mediated RBL-2H3 cell degranulation and passive cutaneous anaphylaxis

Background: Imidacloprid has been commonly used as a pesticide for crop protection and acts as nicotinic acetylcholine receptor agonists. Little information about the relationship between imidacloprid and allergy is available. Objective: This study aims to examine the effects of imidacoprid on IgE-mediated mast cell activation. Methods: The rat basophilic leukemia cell line RBL-2H3 (RBL-2H3 cells) were treated with 10(-3)-10(-12) mol/L imidacloprid, followed by measuring the mediator production, influx of Ca2+ in IgE-activated RBL-2H3 cells, and the possible effects of imidacoprid on antidinitrophenyl IgE-induced passive cutaneous anaphylaxis (PCA). Results: It was shown that imidacoprid suppressed the production of histamine, beta-hexosaminidase, leukotriene C4, interleukin-6, tumor necrosis factor-alpha, and Ca2+ mobilization in IgE-activated RBL-2H3 cells and decreased vascular extravasation in IgE-induced PCA. Conclusion: It is the first time to show that imidacloprid suppressed the activation of RBL-2H3 cells.