髓过氧化物酶在大鼠哮喘中的作用及地塞米松对其的影响

The function and regulation by dexamethasone of myeloperoxidase in rat asthma

目的:观察大鼠哮喘中性粒细胞(PMN)及其髓过氧化物酶(MPO)的表达水平及地塞米松(DM)对其的影响。方法:采用大鼠哮喘模型,随机分成哮喘组(A组)、正常对照组(C组)、地塞米松治疗组(D组),对血PMN进行分离纯化和支气管肺泡灌洗液(BALF)进行细胞计数,免疫组化和比色法测定MPO的表达水平。结果:(1)A组血PMN和支气管壁中MPO的表达水平均显著高于C组(P<0·01);D组血PMN中其表达水平显著低于A组(P<0·01),而在支气管壁两者没有显著性差异(P>0·05)。A组肺组织和BALF中MPO的活性均显著高于C组(P<0·01,P<0·05),D组肺组织中其活性显著性低于A组(P<0·01),而在BALF中两者没有显著性差异(P>0·05)。(2)A组BALF、肺组织中PMN的计数均显著高于C组(P<0·01);D组肺组织中其计数显著高于A组(P<0·01),而两组BALF中PMN占细胞总数的百分比无显著性差异(P>0·05)。结论:PMN及其MPO的表达水平在哮喘时增加,PMN可能通过合成MPO参与了哮喘的炎症过程,DM对其合成功能有抑制作用,但加剧PMN在肺组织中聚集。MPO与气道中PMN的浸润密切相关。

Objective： To observe the numbers of polymorphonuclear leukocyte （PMN） and expressions of myeloperoxidase （MPO） , and influenced by dexamethasone. Methods： In this experiment the rat model of asthma were randomly divided into three groups on average, including asthma group（group A）, control group（group C） and dexamethasone treated group（group D）. Blood PMN were isolated and purified, the total cell numbers and differentiation cell numbers were counted in bronchoalveolar lavage fluid（ BALF）, MPO were detected by immunohistochemistry and chromatometry techniques. Results： （ 1 ） Immunohistochemistry showed that the levels of MPO expressions in purified PMN and bronchial wall in group A were significantly increased than in group C（ P 〈0. 01 ）. They were significantly decreased in purified PMN in group D than in group A （P 〈 0. 01 ） ;while in bronchial wall they were non-significant difference in group D than in group A（ P 〉 0. 05 ）. Activities of MPO expressions were significantly increased in lung tissue and BALF in group A than in group C （P 〈 0. 01, P 〈 0. 05, respectively） ; and they were significantly decreased in lung tissue in group D than in group A （P 〈 0. 01 ）, but there were non-significant difference between in group D and in group A in BALF（ P 〉 0. 05 ）. （2） Numbers of PMN were significantly higher in BALF, bronchial wall and lung tissue in group A than in group C （P 〈0. 01 ） ; they were significantly higher in lung tissue in group D than in group A（ P 〈0. 01 ） ; but the percentage of PMN to total cell number in BALF and numbers of PMN in bronchial wall were non-significant difference in group D than in group A（ P 〉 0. 05 ）. （3）There were a significant correlation between numbers of PMN and protein expressions of MPO in bronchial wall （ r = 0. 857, P 〈 0. 01, n = 27 ）. Conclusion： Levels of PMN and MPO were increased in rat model of asthma. PMN may be involved in the mechanism of asthma via secretion of MPO. And this functions can be inhibitted by dexamethasone. But it can improve PMN influx in lung tissue. MPO are correlated with PMN infiltration in bronchial wall.