基质金属蛋白酶及基质金属蛋白酶组织抑制因子在支气管哮喘发病中作用及早期预防性吸入糖皮质激素的干预研究

目的 探讨基质金属蛋白酶(MMP)及基质金属蛋白酶组织抑制因子(TIMP)与支气管哮喘(简称哮喘)气道重塑的相关性以及预防性吸入激素对气道重塑的干预作用.方法 按随机数字表法将72只清洁级雄性Wistar大鼠分为对照组、哮喘组(卵原蛋白)、干预组(布地奈德+卵原蛋白),每组大鼠24只,分别于雾化激发后第7天、第28天和第35天处死每组大鼠中8只进行气道形态学观察,并采用病理图像分析系统测量大鼠的气道形态学参数.采用免疫组织化学测定肺组织MMP-9、TIMP-1的表达及ELISA方法 检测支气管肺泡灌洗液的上清中MMP-9及TIMP-1的含量.结果 ①与相应对照组相比,28d、35 d哮喘组内管壁厚度、平滑肌厚度、胶原沉积明显增厚(P＜0.05或＜0.01);经治疗后28 d、35 d组平滑肌厚度与相应哮喘组相比差异无统计学意义;而胶原沉积在治疗28 d、35 d组与相应哮喘组相比明显减少(P＜0.01);内管壁厚度治疗35 d组与相应哮喘组相比差异开始下降,但仍高于对照组(P值均＜0.05).②哮喘组支气管肺泡灌洗液中MMP-9及MMP-9/TIMP-1在初始阶段表达上调,在后期下降(P＜0.01);TIMP-1在初始阶段表达上调,在后期亦有下降的趋势,但差异无统计学意义;应用糖皮质激素干预后,在早期MMP-9、TIMP-1及两者比值明显低于哮喘组(P＜0.05),在晚期哮喘组与治疗组无明显差异.结论 哮喘发生、发展过程中,存在MMP-9/TIMP-1的表达失衡,糖皮质激素可能通过调节MMP-9/TIMP-1的平衡,阻抑胶原沉积而干预气道重塑的发生.

Role of MMP/TIMP and interfering effects of eorticosteroid treatment in pathogenesis of bronchial asthma

Objective To investigate the correlations between MMP,TIMP and airway remodeling in brochial asthma(asthma),and the effect of preventive inhaling budesonide(BUD)on airway remodeling.Methods Seventy-two Wistar rats were divided into control group,asthmatic group(sensitized by OVA)and steroids treated group(treated by steroid and sensitized by OVA),each group had 24 rats.The subjects were observed at 3 phases:7 days,28 days,35 days after activation.General histological changes were observed using HE and Masson trichrome stained sections.The parameter of the internal perimeter(Pi),bronchial smooth muscle area(Wam),internal wall area(Wai),and Wc01 collage deposition(Wcol)of the airway were measured by computer-assisted image analysis system.The protein expressions of MMP-9 and TIMP-1 in lung tissue were examined by immunohistochemical analysis and the concentrations of MMP-9 and TIMP-1 in the blood and BALF were quantified by ELISA.Results ①The Wai/Pi,Wam/Pi and Wcol/Pi of asthmatic group in 28 days and 35 days were significantly higher than those of control group(P＜0.05 or P＜0.01);After treatment with BUD the Wam/Pi of 28 days and 35 days BUD treated group had no significant diference with that of corresponding asthmatic group;but the Wcol/Pi of 28 days and 35 days BUD treated group decreased obviously compared with that of asthmatic group(P＜0.01).The Wai/Pi of 35 days BUD treated group was significantly lower than that of the 35 days asthmatic group(P＜0.05),but was significantly higher than the 35 days control group(P＜0.05).②MMP-9 and MMP-9/TIMP-1 increased at the time point of 7 days.but it decreased in the late stage(35 days)of airway remodeling in asthmatic group.And the level of TIMP-1 increased at the time point of 7 days and had a downward trend at the time point of 35 days.After treatment with BUD,MMP-9,TIMP-1 and MMP-9/TIMP-1 increased at the time point of 7 days.but there was no statistic significance between asthmatic group and BUD group in the late stage(35 days).Conclusions The inbalance of MMP-9/TIMP-1 ratios may exist in the progress of asthma.Regulating the balance between MMP-9 and TIMP-1 by steroids may be one of the mechanisms by which airway inflammation and remodeling are inhibited in asthma.