The Study Of The Expression Of Myosin Light Chain Kinase In Bronchial Smooth Muscle Of Asthma Rat Model

Objective: To establish the bronchial asthma model in rat ; To investigate the expression of myosin light chain kinase(MLCK) in bronchial smooth muscle of asthma rat model and explore the role of MLCK in asthmatic pathogenesis; To study the effect of glucocorticoid-dexamethason (DXM) on the expression of MLCK in bronchial smooth muscle of asthma rat model. Methods: Thrity-two male Sprague-Dawley(SD) rats were divided randomly into control group (n=8), asthma model group (challenged for one week, n=8 and challenged for two weeks, n=8), and DXM group (n=8) after having been fed to adapt them to the new environment for one week. Asthma model was established by sensitization and challenge with ovalbumin (OVA), control group with normal saline. One hour prior to OVA challenge, the DXM group rats were intraperitoneally injected with DXM 0.5mg/kg. The establishment of asthma model was judged by the examination of the total white cell, eosinophil cell counts in bronchoalveolar lavage fluid (BALF), and Hematoxylin and Eosin (HE)stain of lung histologic section of rat and the reaction of rats. The expression of bronchial smooth muscle MLCK was detected by immunohistochemistry and Western-Bloting methods. Results: The bronchial asthma rat model was successfully established. The count of total white cells and eosinophils in rat BALF in asthma mode group was significantly higher than those in control group and DXM group(P<0.01). Pathologial findings of lung of bronchial asthma mode group were bronchial constriction, part of epithelium shedding, inflammatory cell including eosinophils and lymphocytes infiltrating around the airways and blood vessels, but only a little of the same cell around the airways and...