Effects of o-VA on the degranulation of mast cells. (A, B) RBL-2H3 cells were pretreated with or without o-VA and Dexa, then incubated for 24 h. The absorbance intensity was detected using a spectrophotometer. (C, E) RBL-2H3 cells and RPMCs were pretreated with or without o-VA. Histamine levels were detected using a fluorescence plate reader. (D) β-Hexosaminidase levels were detected using a spectrophotometer. (F) RBL-2H3 cells were preincubated with Fluo-3/AM. Intracellular calcium was detected using a fluorescence plate reader. BAPTA, a calcium chelator, was used as a positive control. Each data point represents the mean±SEM of three independent experiments. *P<0.05. Dexa: dexamethasone.