Inhibition effects of Moutan Cortex Radicis on secretion of eotaxin in A549 human epithelial cells and eosinophil migration

Eosinophils have been implicated in a broad range of diseases, most notably allergic conditions (e.g. asthma, rhinitis and atopic dermatitis) and inflammatory diseases. These diseases are characterized by an accumulation of eosinophils in the tissue. Defining the mechanisms that control eosinophil recruitment is fundamental to understanding how these diseases progress and may identify a novel target for drug therapy. Eotaxin is a potent eosinophil-specific chemokine that is released in the respiratory epithelium after allergic stimulation. Aim of the study: In this study, we determined whether Moutan Cortex Radicis (MCR), a plant extract, effects eotaxin secretion from A549 epithelial cells and eosmophil chemotaxis, and then examined the mechanism involved. Materials and methods: Prior to assaying MCR's effects, A549 cells were stimulated with tumor necrosis factor-alpha. TNF-alpha, interleukin-4 (IL-4) and IL-1 beta to induce expression of chemokines and adhesion molecules involved in eosinophil chemotaxis. In the presence of MCR, eotaxin, regulated on activation in normal T cells expressed and secreted (RANTES), IL-8, IL-16, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) transcripts were quantitated by real-time RT-PCR. Results: As a result, 0.01, 1, and 100 mu g/ml of MCR treatments reduced eotaxin expression significantly and 0.01, 0.1, 1, 10, and 100 mu g/ml of MCR reduced significantly eotaxin secretion. In addition, MCR treatment significantly inhibited eosinophil migration toward A549 medium. And 100 mu g/ml of MCR suppressed the activated of nuclear factor (NF)-kappa B. Conclusions: These findings indicate that suppressed eotaxin secretion by MCR treatment is due to the inhibition of NF-kappa B activation. Therefore, MCR might be of therapeutic value in treating asthma. (c) 2007 Published by Elsevier Ireland Ltd.