1,25-(OH)_2D_3对哮喘小鼠肺内高迁移率族蛋白B1及Toll样受体4表达的影响

Effect of 1,25-(OH)_2D_3 on expression of HMGB1 and TLR4 in the lungs of asthmatic mice

目的观察1,25-(OH)2D3对哮喘小鼠气道重塑、肺组织高迁移率族蛋白B1(HMGB1)及Toll样受体4(TLR4)表达的影响。方法 30只雌性BALB/c小鼠随机分为对照组、哮喘组和1,25-(OH)2D3干预组。采用卵清蛋白腹腔注射致敏联合雾化吸入激发建立哮喘小鼠模型,干预组于每次激发前0.5 h给予腹腔内注射1,25-(OH)2D3,对照组以生理盐水代替。苏木精-伊红染色观察小鼠气道结构变化;采用RT-PCR法从mRNA水平及免疫组化法从蛋白质水平检测HMGB1及TLR4表达的变化;同时对相关变量进行Pearson相关分析。结果哮喘组气道壁厚度较对照组明显增厚,干预组较哮喘组气道壁增厚程度明显减轻(P<0.05)。哮喘组HMGB1、TLR4的mRNA和蛋白表达水平均较对照组增高(均P<0.05);而干预组HMGB1、TLR4的mRNA和蛋白表达水平均较哮喘组降低,但仍高于对照组(均P<0.05)。肺组织内HMGB1蛋白与TLR4蛋白的表达呈正相关(P<0.01),HMGB1 mRNA及TLR4 mRNA的表达亦呈正相关(P<0.01)。结论在哮喘气道重塑模型中,HMGB1及TLR4可能参与哮喘气道重塑过程;1,25-(OH)2D3可改善哮喘小鼠气道重塑,其机制可能与降低哮喘小鼠肺内HMGB1及TLR4的表达有关。

Objective To investigate the effects of 1,25-（OH）2D3 on the airway remodeling and expression of high-mobility group box 1 （HMGB1） and Toll-like receptor 4 （TLR4） in the lungs among asthmatic mice. Methods Thirty female mice （BALB/c strain） were randomly divided into control, asthma and 1,25-（OH）2D3 intervention groups. An asthmatic mouse model was established by intraperitoneal injection and aerosol inhalation of ovaibumin. The intervention group was given 1,25-（OH）2D3 by intraperitoneal injection 0.5 hour before each aerosol inhalation, while the control group used normal saline instead. The hematoxylin-eosin staining was used to observe the mouse airway structural changes. The mRNA and protein expression of HMGB 1 and TLR4 was measured by RT-PCR and immunohistochemistry, respectively. Pearson correlation analysis was performed. Results The asthma group had a significantly increased airway wall thickness compared with the control group （P〈0.05）; the intervention group had a significantly lower increase in airway wail thickness than the asthma group （P〈0.05）. The mRNA and protein expression of HMGB1 and TLR4 was significantly higher in the asthma group than in the control group （P〈0.05）, the mRNA and protein expression of HMGB1 and TLR4 in the intervention group was significantly lower than that in the asthma group, but still higher than that in the control group （P〈0.05）. A positive correlation was found between the protein expression of HMGB1 and TLR4 （P〈0.01）, and so was their mRNA expression （P〈0.01）. Conclusions HMGBI and TLR4 may be involved in asthmatic airway remodeling. 1,25-（OH）2D3 can reduce the airway remodeling in asthmatic mice, which may be related to the downregulation of HMGB1 and TLR4 expression in the lungs of asthmatic mice.