Distribution and expression of matrix metalloproteinase-9 in lung tissues of patients with chronic obstructive pulmonary disease

Objective To evaluate the distribution and expression of matrix metalloproteinase (MMP)-9 in the lung tissues of COPD patients and its correlation with the level of airflow obstruction,respiratory failure,quality of life and dyspnoea.The purpose is to provide the new idea about its prevention and the therapy of COPD for clinic.Methods Totally sixty-three edge lung tissue samples (the distance of tumor tissue ＞5 cm) were selected from the chest surgical excision of lung tumor patientes in Thoracic Surgery,Pneumosurgery at the General Hospital,Tianjin Medical University.These tissue samples were assigned into non-smokers without COPD(A group) group,COPD patients without smoking (B group) group,mild COPD patients with smoking (C group) group,moderate COPD patients with smoking (D group) group,and severe COPD patients with smoking (E group) group.FEV1,FEV1％pred,FEV1/FVC,MEF50％pred,MEF25 ％pred,PaO2,PaCO2 of those were also tested respectively by pulmonary function instrument and blood gas analyzer,quality of life and the level of dyspnoea of those were also evaluated respectively by grading the scale of CAT,MMRC.The lung tissue pathology was observed with HE staining.Immunohistochemical staining was used to investigate the distribution and expression of MMP-9 in the lung tissues,and the correlative analysis was conducted.Results ①(a)FEV1 (L):There was statistical significant differences between each two different D,E and each two different A,B,C group in FEV1 (P ＜0.05).There was statistical significant differences between D and E group (P ＜0.05).FEV1/FVC(％):There was statistical significant differences between each two different A,B,C,D and E group in FEV1/FVC percentage (P ＜0.05),except between A and B group (P ＞0.05).(b)PaO2:There was statistical significant differences between each two different A,B,C,D and E group inPaO2(P＜0.05),except between A,B group,and B,C group (P＞0.05).(c)The scale of CAT and MMRC:There was statistical significant differences between each two different A,B,C,D and E group in the scale of CAT and MMRC (P ＜0.05),except between A,B group,and B,C group (P ＞0.05).②The alveoli of moderate and severe COPD patients have been significantly destroyed,the airway have remodeled,inflammation appeared in airway,the bronchus wall and the pulmonary alveoli have been filled with inflammatory cell,extracellular matrix have been apparently degradated.③The number of MMP-9 positive cells of moderate and severe COPD patients was significantly higher than that of mild COPD patients and patients without COPD.There was statistical significant differences between each two different A,B,C,D and E group in the positive expression of MMP-9 (P ＜0.05).The positive expression of MMP-9 in COPD group has the trend to ascend.④The correlation analysis:the expressions of MMP-9 in the five group was negative correlation with the FEV1,FVC％pred,FEV1/FVC,MEF50％pred,MEF25％pred (r =-0.504,P =0.009; r =-0.512,P =0.009; r =-0.534,P =0.008; r =-0.463,P =0.01; r =-0.461,P =0.015),negative correlation with the level of PaO2 (r =-0.450,P =0.032) and positive correlation with the Scale of CAT,classification of MMRC (r =0.455,P =0.016; r =0.452,P =0.018).Conclusions ①It was suggested that smoking can promot the expression of MMP-9 conditon.②It was suggested that the expression of MMP-9 increased as the COPD got worse.③It was suggested that the expression of MMP-9 was correlation with declining lung function decline,quality of life,COPD patients' conditon. Key words: Chronic obstructive pulmonary disease ;  Matrix metalloproteinase ;  Smoking ;  Pulmonary function ;  Blood gas analysis ;  Inflammation