哮喘豚鼠气道重构中基质金属蛋白酶-9及抑制物TIMP-1的表达

Expressions of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in airway remodeling of asthmatic guinea pigs

目的:探讨哮喘豚鼠模型中基质金属蛋白酶(MMPs)及其组织抑制因子(TIMP)在哮喘气道重构发病中的作用.方法:重复雾化吸人卵蛋白建立豚鼠哮喘气道重构模型.实验分为对照组、哮喘激发4,6和8wk组.免疫组化方法结合显微图像分析检测MMP9,TIMP1的表达.半定量PCR检测MMP9及TIMP1mRNA水平.结果:①哮喘各组动物均出现管壁增厚、平滑肌增生等气道重构的特征性改变.②哮喘豚鼠MMP9的mRNA表达:哮喘4wk组为(0.52±0.05),哮喘6wk组为(0.74±0.05);哮喘8wk组为(0.48±0.04);对照组为(0.21±0.04);哮喘各组与对照组组间比较差异有统计学意义(P<0.05).哮喘豚鼠TIMP1的mRNA水平:哮喘4wk组为(0.36±0.04);哮喘6wk组为(0.83±0.05);哮喘8wk组为(0.97±0.05);对照组为(0.20±0.02);哮喘各组与对照组组间比较差异有统计学意义(P<0.05).③免疫组化的结果和RTPCR的结果一致.④在哮喘各时段组中,MMP9的表达增高自第4wk时明显变缓,而TIMP1仍持续增高,导致MMP9/TIMP1比例下降.结论:哮喘的气道重构与MMP9和TIMP1的表达密切相关,而二者的比例可能反映气道重构的严重程度.

AIM： To investigate the roles of matrix metalloproteinase-9 （MMP-9） and tissue inhibitor of metalloproteinase-1 （TIMP-1） in airway remodeling of asthmatic guinea pigs. METHODS： Guinea pigs were sensitized with ovalbumin conjunctod with A1 （ OH ） 3, and subsequently challenged repeatedly with ovalbumin aerosol. The guinea pigs were randomly divided into the control group, asthmatic 4, 6, 8-week groups. The expressions of MMP-9 and TIMP-1 in bronchi and lung tissues were observed by immunohistochemistry combined with the micro-image analysis. The levels of MMP-9 mRNA and TIMP-1 mRNA were determined by semi-quantitative PCR. RESULTS： ① After repeated allergen challenge, smooth muscle hyperplasia was obvious in guinea pig bronchi. Expression levels of MMP-9 and TIMP-1 in the epithelial cells of bronchi were significantly higher in asthmatic animals than those of control group. ② The expression of MMP-9 in asthmatic guinea pigs＇ lung tissues was 0.52 ± 0.05 in 4-week group, 0.74 ± 0.05 in 6-week group, 0.48 ± 0.04 in 8-week group , 0.21 ± 0.04 in control group （ P 〈 0.05 ）. The expression of TIMP-1 in asthmatic guinea pigs＇ lung tissues was 0.36 ± 0.04 in 4-week group ,0.83± 0.05 in 6-week group, 0.97 ± 0.05 in 8-week group , 0.20 ± 0.02 in control group （ P 〈 0.05 ）. ③ The results of immunoeytochemistry were consistent with those of RT-PCR.④ The up-regulation of MMP-9 expression become slower than TIMP-1 since the 4th week in asthmatic animals. So ratio of MMP-9/ TIMP-1 was decreased. CONCLUSION： The expression levels of MMP-9 and TIMP-1 were closely correlated with asthma airway remodeling, and the ratio of MMP-9/TIMP-1 may reflecte the degree of asthma airway remodeling.