吸烟对致敏大鼠肺组织基质金属蛋白酶9及其抑制剂1表达的影响

目的 通过观察吸烟对致敏大鼠肺组织基质相关因子基质金属蛋白酶9(matrix metalloproteinase-9,MMP-9)及金属蛋白酶组织抑制因子1(tissue inhibitor of metallopmteinase-1,TIMP-1)表达的影响,探讨吸烟在支气管哮喘(简称哮喘)气道重塑中的作用.方法 24只雄性Wistar大鼠随机分为对照组、致敏组和吸烟致敏组,每组8只.后两组用卵白蛋白(OVA)致敏并长期(8周)吸人激发,制备哮喘模型,在激发第3周开始,吸烟致敏组大鼠置于自制熏箱内进行被动吸烟.采用免疫组织化学法检测大鼠气道上皮细胞MMP-9、TIMP-1的蛋白表达,同时测量支气管壁的厚度,并用逆转录-聚合酶链反应法检测各组肺组织的MMP-9 mRNA、TIMP-1 mRNA含量.结果 ①吸烟致敏组气道壁厚度[(23.28±2.38)μm2/μm]明显高于致敏组[(20.06±2.94)/μm2/μm]和对照组[(11.64±2.42)μm2/μm](P值均＜0.05),致敏组高于对照组(P＜0.05),②吸烟致敏组肺组织中MMP-9 mRNA表达(0.49±0.02)和气道上皮细胞MMP-9蛋白含量(32.78±2.60)均明显高于致敏组(0.41±0.04,23.05±2.11)和对照组(0.23±0.03,15.88±1.69)(P值均＜0.01),致敏组高于对照组(P值均＜0.01),③吸烟致敏组肺组织中TIMP-1mRNA表达(0.53±0.02)和气道上皮细胞TIMP-1蛋白含量(34.54±2.90)均高于致敏组(0.37±0.05,21.25±2.28)和对照组(0.235=0.04,15.78±1.97)(P值均＜0.01),致敏组高于对照组(P值均＜0.01);④肺组织MMP-9/TIMP-1 mRNA比值:吸烟致敏组(0.91±0.05)低于致敏组(1.12±0.06)和对照组(1.03±0.09)(P值均＜0.01).致敏组高于对照组(P＜0.01),⑤气道上皮细胞MMP-9/TIMP-1蛋白含量比值:吸烟致敏组(0.94±0.03)低于致敏组(1.09±0.07)和对照组(1.01±0.06)(P＜0.05,P＜0.01),致敏组高于对照组(P＜0.01).结论 吸烟可使致敏大鼠肺组织MMP-9和TIMP-1过度表达,比例失调,加重气道重塑.

Effect of smoking on expressional level of matrix metalloproteinase-9 and its inhibitor-1 in sensitized rats

Objective To observe the effect of smoking on the expressional levels of lung tissue base correlation factor:matrix metallopmteinase-9(MMP-9)and its inhibitor,tissue inhibitor of metalloproteinase-1 (TIMP-1)in sensitized rats,and investigate the role of smoking in the processes of airway remodeling of asthma.Methods Twenty-four male Wistar rats were divided randomly into control group,sensitized group and smoking sensitized group.The rats of latter two groups were sensitized and challenged by ovalbumin to establish the asthmatic model.From the challenged third weeks,the smoking sensitized group rats were put in the self-made fumigating box to smoke passively.The expressions of genes and their products of MMP-9 and TIMP-1 in lung tissue were defected using immunohistochemistry,RT-PCR in all rats of four groups,and the total bronchial wall area was measured by image analysis system.Results ①The bronchial wall thickness of the smoking sensitized group(23.28±2.38)μm2/μm was significantly higher than that of the sensitized group(20.06±2.94)μm2/μm and the control group(11.64±2.42)μm2/μm,(all P＜0.05),so did the sensitized group and the control group(P＜0.05).②The expression of lung tissue MMP-9 mRNA (0.49±0.02)and the protein levels of airway endothelial cell MMP-9(32.78±2.60)were significantly higherthan those of the sensitized group(0.41±0.04,23.05±2.11)and the control group(0.23±0.03,15.88±1.69,all P＜0.01),SO did the sensitized group and the cOntrOl group(P＜0.01).③The expression of lung tissue TIMP-1mRNA(0.53±0.02)and the protein levels of airway endothelial cell TlMP-1(34.54±2.90)were significantly higher than those of the sensitized group(0.37±0.05,21.25±2.28)and the control group(0.23±0.04,15.78±1.97,all P＜0.01),so did the sensitized group and the control group(P＜0.01).④The ratio in lung tissue between MMP-9 mRNA and TIMP-1mRNA of the smoking sensitized group was lower than that of the sensitized group(1.12±0.06)and the control group(1.03±0.09,all P＜0.01),but the ratio of the sensitized group was higher than that of the control group(P＜0.01).⑤The ratio of protein levels in airway endotheliaI cell between MMP-9 and TlMP-1,in the smoking sensitized group(0.94±0.03)was lower than that in the sensitized group(1.09±0.07)and the control group(1.01±0.06,P＜0.05,P＜0.01),but the ratio of the sensitized group was higher than that of the control group (P＜0.01).Conclusions Smoking can cause MMP-9 and TIMP-1 overexpression,disproportion and increase airway remodeling in the lung tissue of the smoking sensitized rats.