Li Chang-chong, Ye Le-ping, Chen Xiao-fang, Li Shao-bo, Cai Xiao-hong, Dong Lin, Luo Yun-chun, Zhang Zheng-xia
Department of Respiratory Medicine, Yuying Children's Hospital Affiliated to Wenzhou Medical College, Wenzhou 325027, China.
Zhonghua Er Ke Za Zhi. 2005 Jul;43(7):521-5.
To study the expression of signal transducer and activator of transcription 6 and its mRNA in rat asthma model and the modulatory effect of dexamethasone (DXM).
Thirty male SD rats were randomly divided into three groups: the control group, asthma group and DXM group. The rats in each group were sacrificed 24 h after the last challenge. In the experiment, the rat model of asthma was established by ovalbumin (OVA) challenge method. The lung tissue was taken from the left lung, and bronchoalveolar lavage fluid (BALF) was collected from the right lung. The total cell numbers, eosinophils (EOS) count and differentiated cell counts in BALF were performed on different count fluids. The concentrations of IL-4 in serum and BALF were measured by using sandwich ELISA. The protein expressions of STAT6 were detected with immunohistochemical techniques. The mRNA expressions of STAT6 were detected with in situ hybridization.
(1) The total cell counts in BALF, the absolute counts of EOS, and the ratios of eosinophils to the total cell numbers (EOS%) of asthma group were all significantly higher than those of the control group (P < 0.01). The total cell counts in BALF, the absolute counts of EOS, and EOS% of DXM group were all significantly lower than those of asthma group (P < 0.01). (2) The concentrations of IL-4 in BALF and serum of asthma group [(25.7 +/- 7.4) ng/L, (34.2 +/- 10.5) ng/L] were significantly higher than those of control group [(8.6 +/- 3.0) ng/L, (12.1 +/- 2.9) ng/L] (P < 0.01). The concentrations of IL-4 in BALF and serum of DXM group were significantly lower than those of asthma group. (3) Immunohistochemistry showed that the protein content of STAT6 around the bronchus of asthma group (0.171 +/- 0.025) was significantly higher than that of the control group (0.082 +/- 0.022) (P < 0.01), while that of DXM group (0.114 +/- 0.013) was significantly lower than that of asthma group. The epithelial cells were the cells. In situ hybridization showed that the mRNA expression of STAT6 around the bronchus of asthma group (0.180 +/- 0.013) was significantly higher than that of the control group (0.091 +/- 0.012) (P < 0.01), while that of DXM group (0.114 +/- 0.010) was significantly lower than that of asthma group. (4) There was a significant correlation between the concentration of IL-4 in BALF, the content of STAT6 and STAT6 mRNA, respectively, in the epithelial cells of bronchus. There was a significant correlation between the absolute numbers of EOS and EOS% in BALF, the content of STAT6 and STAT6 mRNA, respectively, in the epithelial cells of bronchus.
STAT6 protein and STAT6 mRNA were found strongly expressed in rat asthma model and the epithelial cells were the chief expressing cells. Dexamethasone had an inhibitory effect on airway inflammatory cells infiltration. It significantly depressed STAT6 and mRNA expression. Which may be a key process in modulatory mechanism of asthma.
研究信号转导子和转录激活子6（STAT6）及其mRNA在大鼠哮喘模型中的表达以及地塞米松（DXM）的调节作用。
将30只雄性SD大鼠随机分为三组：对照组、哮喘组和DXM组。在末次激发后24小时处死每组大鼠。实验中，采用卵清蛋白（OVA）激发法建立大鼠哮喘模型。取左肺组织，收集右肺支气管肺泡灌洗液（BALF）。对不同计数液进行BALF中总细胞数、嗜酸性粒细胞（EOS）计数及分化细胞计数。采用夹心ELISA法检测血清和BALF中IL-4的浓度。用免疫组织化学技术检测STAT6的蛋白表达。用原位杂交法检测STAT6的mRNA表达。
（1）哮喘组BALF中总细胞计数、EOS绝对计数及嗜酸性粒细胞占总细胞数的比例（EOS%）均显著高于对照组（P<0.01）。DXM组BALF中总细胞计数、EOS绝对计数及EOS%均显著低于哮喘组（P< 0.01）。（2）哮喘组BALF和血清中IL-4浓度[（25.7±7.4）ng/L，（34.2±10.5）ng/L]显著高于对照组[（8.6±3.0）ng/L，（12.1±2.9）ng/L]（P< 0.01）。DXM组BALF和血清中IL-4浓度显著低于哮喘组。（3）免疫组织化学显示，哮喘组支气管周围STAT6蛋白含量（0.171±0.025）显著高于对照组（0.082±0.022）（P< 0.01），而DXM组（0.114±0.013）显著低于哮喘组。上皮细胞为主要表达细胞。原位杂交显示，哮喘组支气管周围STAT6 mRNA表达（0.180±0.013）显著高于对照组（0.091±0.012）（P< 0.01），而DXM组（0.114±0.010）显著低于哮喘组。（4）支气管上皮细胞中BALF中IL-4浓度、STAT6含量及STAT6 mRNA之间分别存在显著相关性。BALF中EOS绝对数和EOS%、支气管上皮细胞中STAT6含量及STAT6 mRNA之间分别存在显著相关性。
在大鼠哮喘模型中发现STAT6蛋白和STAT6 mRNA强烈表达，上皮细胞是主要表达细胞。地塞米松对气道炎症细胞浸润有抑制作用。它显著降低STAT6及其mRNA表达。这可能是哮喘调节机制中的关键环节。
