Effect of Dexamethasone on the expression of heme oxygenase-1 in the lung tissue of asthmatic rats

Objective(1)To investigate the protein expressions of HO-1 in the lung tissue of asthmatic rats;(2)To research whether the ratios of eosinophils to the total cell numbers(EOS%)in BALF,the numbers of eosinophils in lung tissue(EOS),the percent content of blood carbon monoxide Hb(COHb) and the expressions of HO-1 have a correlation in the lung tissue of asthmatic rats;(3)To study the regulation role of dexamethasone on HO-1.Methods Thirty Sprague-Dawley(SD)male rats were randomly divided into 3 subgroups:the control group(N group),asthma group(A group),DM group(D group),each subgroup had 10 rats.The assessment of the percent content of blood carbon monoxide Hb(COHb)was performed.The total cell number,differentiation cell numbers in bronchoalveolar lavage fluid(BALF)and the inflammatory cells of airway wall were observed,the protein expressions of HO-1 in airway wall was detected by immunohistochemistry techniques.Results The expression of HO-1 was mainly located in airway epithelium in the 3 groups(N,A,D)with the optical densities being 0.07±0.01,0.22±0.03,0.12±0.02,respectively.The group A showed higher optical densities than that of the group N(P0.001),the protein expressions of HO-1 in airway wall of group D was significantly lower than those of group A(P0.01).There was a significant correl ation between the expression of HO-1 in airway wall and the percent content of COHb(r=0.916,P0.01),EOS% in BALF(r=0.874,P0.01),and the numbers of EOS in lung tissue(r=0.895,P0.01).Conclusion The expression of HO-1 increases significantly in the lung tissue of asthmatic rat,suggesting HO-1 might play a significant role in the pathogenesis of asthma.DM demonstrates anti-inflammatory effects partly by downregulating the expressions of HO-1.