检测哮喘大鼠肺组织、肺泡灌洗液及血清中MMP-9,TIMP-1的意义

Significance of the matrix metalloproteinase 9 and tissue inhibitor metalloproteinase 1 in lung tissues,BALF andserum of asthma rats

目的:探讨基质金属蛋白酶(MMP-9),组织金属蛋白酶抑制物(TIMP-1)在哮喘大鼠发病中的作用及与气道重塑的关系.方法:将20只幼年Wistar大鼠随机分为正常对照组、哮喘模型组,每组10只.采用卵蛋白(OVA)等致敏大鼠哮喘模型,第14日后用10 g/L卵蛋白溶液雾化吸入,20 min激发,1次/d,持续6 wk;对照组用生理盐水雾化吸入.观察两组动物哮喘发作症状、气道壁厚度、平滑肌层厚度及胶原沉积情况;免疫组化染色检测MMP-9和TIMP-1的表达;ELISA检测血清、肺泡灌洗液中MMP-9和TIMP-1水平,并了解其与组织表达量的相关性.结果:哮喘模型组肺组织MMP-9,TIMP-1表达明显降低,其气道壁、平滑肌的厚度明显大于正常对照组,其血清和肺泡灌洗液的水平明显高于正常对照组,差异具有显著性统计学意义(P<0.01).血清和肺泡灌洗液的MMP-9,TIMP-1水平与气道壁的厚度、平滑肌层的厚度以及胶原面积呈正相关,与组织中MMP-9,TIMP-1的表达成负相关.结论:MMP-9,TIMP-1参与了气道重塑的过程;检测血清和肺泡灌洗液中MMP-9和TIMP-1的水平对哮喘的临床诊断具有指导意义.

AIM： To explore the roles of matrix metalloproteinase 9（MMP-9） and tissue inhibitor metalloproteinasc 1 （ TIMP-1 ） in the morbidity of asthma and their relation with airway remodeling. METHODS： Twenty young Wistar rats were randomly divided into normal control group and asthma model group, with 10 in each group. Ovalbumin （OVA） was adopted for sensitizing asthma rat model. After 14 d, 1% ovalbumin solution aerosol was given to rats of asthma model group, which had been excited for 20 min, once daily for 6 weeks. Aerosol inhalation with normal saline was adopted for control group. Asthmatic attack symptoms, airway wall thickness, thickness of smooth muscle and collagen deposition were observed in each group. MMP-9 and TIMP-1 levels in serum and BALF of experimental rats were detected by ELISA and their relationship with MMP-9 and TIMP-1 expression in lung tissues was analyzed. RESULTS： MMP-9 and TIMP-1 expression was reduced significantly in lung tissues of asthma model and their airway walls and smooth muscle thickness were significantly higher than those in control group. The serum and BALF MMP-9 and TIMP-1 levels were significantly higher in asthma model than those in normal control group, with statistically significant difference. MMP-9 and TIMP-1 levels in serum and BALF were positively correlated with airway wall thickness, smooth muscle thickness and collagen area, and negatively correlated with MMP-9 and TIMP-1 expression in lung tissues. CONCLUSION： MMP-9 and TIMP-1 are involved in the airway remodeling process. MMP-9 and TIMP-1 levels in serum and BALF are of some significance for clinical diagnosis.