Expression Of Matrix Metalloproteinase-9 And Tissue Inhibitor Of Metalloproteinase-1 In Rat Lung Tissue And Human Vascular Endothelioal Cell After Cigarette-Smoking Exprosure

Objective: To study the expression of matrix metalloproteinase-9(MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) inthe rat lung tissue and vascular endothelial cell after cigarette-smokingexposure.Methods: Twenty-four male SD rats were randomly divided into anormal control (N) group and a COPD model (M) group. The N group andM group were randomly subdivided into N₁ subgroup,N₂ subgroup andM₁ subgroup,M₂ subgroup. The rat model of COPD was established byexposure to cigarette-smoking. Rats' general condition, weight changes,lung function, pathologic features of lung tissues and inflammatory celldifferentials in bronchoalveolar lavage fluid(BALF) were investigated.Immunohisto-chemistry and Western Blot were carried out to examine theexpression intensity of MMP-9 and TIMP-1 in lung tissue. Vascularendothelial cell were stimulated by different concentration ofcigarette-smoking extractive and Western Blot were carried out toexamine the expression of MMP-9 and TIMP-1.Results. Statistic analysis showed weight[(380.63±42.24) g vs(299.51±30.11) g, respectively], FEV_0.3[(4.20±0.25) ml vs (1.86±0.22)ml], FEV_0.3/FVC[(85.56±5.85)% vs (65.06±8.40)%], PEF[(47.24±7.28) ml/s vs (18.84±1.56) ml/s] were significantly decreased in M group as compared with N group (p＜0.05), while total leukocyte counts[(1.92±0.43)×10⁸/L vs (5.25±0.50)×10⁸/L], neutrophil counts[(0.08±0.03)×10⁸/L vs (0.95±0.16)×10⁸/L], neutrophil proportion[(4.28±1.35)% vs (17.97±2.15)%] were significantly increased in M groupas compared with N group (p＜0.05). MLI(77.32±28.73) in M group washigher than that (43.96±7.16) in N group while MAN was decreased inM group (232.00±97.19) compared with N group (392.84±24.41) (allp＜0.05). Integrated optical density (IOD) for MMP-9 (126.31±22.46)and TIMP-1 (161.34±22.45) in M group was higher than those [(56.35±15.69),(57.02±15.76)] in N group. While the ratio ofMMP-9/TIMP-1 decreased in M group (0.77±0.11) compared with Ngroup (0.99±0.04) (p＜0.05). Results from western blot showed that theexpression of MMP-9 and TIMP-1 was higher in M group than in Ngroup and that in vascular endothelial cell with the increase inconcentration of CSE, they became higher and higher.Conclusions: Cigarette-Smoking can induce rats' COPD andabnormal secretion of MMP-9 and TIMP-1. The proteolytic enzymeproduced by vascular endothelial cell may play a important role in thepathogenesis of COPD.