[哮喘气道重塑中气道平滑肌细胞凋亡的变化及地塞米松对大鼠的影响]

[Changes of airway smooth muscle cell apoptosis in asthmatic airway remodeling and the effect of dexamethasone in rats].

作者信息

Ding Min-Jiao, Wang Liang-Xing, Dai Yuan-Rong

机构信息

Department of Respirology, the First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, China.

出版信息

Zhonghua Jie He He Hu Xi Za Zhi. 2008 Aug;31(8):607-10.

PMID:19080409

Abstract

OBJECTIVE

To observe the changes of airway smooth muscle cells (ASMC) apoptosis in the airway remodeling process of asthma, and to evaluate the effect of dexamethasone on ASMC apoptosis and the possible mechanisms.

METHODS

Thirty six male Sprague-Dawley rats were randomly divided into 3 groups, including a control group, an asthma group and a dexamethasone treated group. The rats were sensitized with ovalbumin and Al(OH)(3), and repeatedly exposed to aerosolized ovalbumin. ASMC apoptosis was measured by the technique of TdT-mediated dUTP-biotin nick end labeling (TUNEL). Bcl-2 protein and mRNA, and Bax protein and mRNA in airway smooth muscles were measured by immunohistochemistry and in situ hybridization respectively. SPSS version 11.5 was used for statistical analysis. Data were presented as ((-x) +/- s), and means were compared with analysis of variance. The correlation of two variables was analysed by linear correlation analysis.

RESULTS

The apoptosis index (AI) of ASMC was separately 0.201 +/- 0.022, 0.030 +/- 0.016, 0.118 +/- 0.043 in the control, the asthma, and the dexamethasone asthma, treated group. Immunohistochemistry showed that the expression of Bcl-2 protein (A) in airway smooth muscles in above groups was 0.060 +/- 0.012, 0.112 +/- 0.028 0.080 +/- 0.010. In situ hybridization showed that the level of Bcl-2 mRNA in airway smooth muscles in the control, the asthma, and the dexamethasone treated group was 0.065 +/- 0.019, 0.157 +/- 0.019 and 0.099 +/- 0.029. The expression of Bax protein in each group was 0.120 +/- 0.020, 0.062 +/- 0.012 and 0.093 +/- 0.010 respectively. Accordingly the level of Bax mRNA in each group was 0.155 +/- 0.025, 0.074 +/- 0.019 and 0.118 +/- 0.031 respectively. The AI of ASMC was negatively correlated with Wam/Pbm (r = -0.860, P < 0.01) and the relative content of Bcl-2 protein (r = -0.783, P < 0.01), but was positively correlated with the relative content of Bax protein (r = 0.873, P < 0.01).

CONCLUSIONS

The reduction of ASMC apoptosis may participate in the remodeling process of asthma. Dexamethasone induces ASMC apoptosis possibly by the increase of Bax expression and the decrease of Bcl-2 expression in airway smooth muscles.

摘要

目的

观察哮喘气道重塑过程中气道平滑肌细胞（ASMC）凋亡的变化，评价地塞米松对ASMC凋亡的影响及其可能机制。

方法

将36只雄性Sprague-Dawley大鼠随机分为3组，即对照组、哮喘组和地塞米松治疗组。用卵白蛋白和氢氧化铝致敏大鼠，并反复暴露于雾化卵白蛋白。采用TdT介导的dUTP-生物素缺口末端标记技术（TUNEL）检测ASMC凋亡。分别用免疫组织化学和原位杂交法检测气道平滑肌中Bcl-2蛋白和mRNA、Bax蛋白和mRNA。采用SPSS 11.5版进行统计分析。数据以（-x）±s表示，组间均值比较采用方差分析。两变量的相关性采用线性相关分析。

结果

对照组、哮喘组和地塞米松治疗组ASMC的凋亡指数（AI）分别为0.201±0.022、0.030±0.016、0.118±0.043。免疫组织化学显示，上述各组气道平滑肌中Bcl-2蛋白（A）表达分别为0.060±0.012、0.112±0.028、0.080±0.010。原位杂交显示，对照组、哮喘组和地塞米松治疗组气道平滑肌中Bcl-2 mRNA水平分别为0.065±0.019、0.157±0.019、0.099±0.029。各组Bax蛋白表达分别为0.120±0.020、0.062±0.012、0.093±0.010。相应地，各组Bax mRNA水平分别为0.155±0.025、0.074±0.019、0.118±0.031。ASMC的AI与Wam/Pbm（r=-0.860，P<0.01）和Bcl-2蛋白相对含量（r=-0.783，P<0.01）呈负相关，与Bax蛋白相对含量呈正相关（r=0.873，P<0.01）。