Inhibitory effects of azelastine on superoxide anion generation from activated inflammatory cells measured by a...

Blood was drawn from healthy human volunteers and neutrophils and eosinophils were purified on a Conray-Ficoll and a Percoll gradient, respectively. Rat mast cells were also purified on a Percoll gradient. Superoxide anion (O2-) generation from the cells were measured by 2-methyl-6-[p-methoxy-phenyl]-3,7-dihydroimidazo[1,2-a]pyrazin+ ++-3-one (MCLA)-dependent luminescence. Addition of 0.5 mumol/l MCLA and a stimulatory agent, such as phorbol myristate acetate, N-formyl-methionyl-leucyl-phenylalanine (fMLP) and compound 48/80, to a suspension of each cell caused a marked luminescence which was inhibited by 0.5 mumol/l superoxide dismutase (SOD). Azelastine (A-5610) significantly inhibited the O2- generation from each activated inflammatory cell in a dose-dependent manner. When eosinophils were activated by fMLP in the presence of cytochalasine (CB), azelastine abolished the luminescence stronger than that from the fMLP-stimulated cells in the absence of CB.