PURPOSE: To explore the effects of smoking intensity,duration and cessation on mRNA and protein expression of matrix metalloproteinase-12(MMP-12) in airway epithelium of rats,and its implication in the pathogenesis of chronic obstructive pulmonary disease(COPD).
METHODS: Forty Wistar rats were randomly divided into five group(control group,long-term heavy smoking group,short-term heavy smoking group,long-term light smoking group and smoking cessation group which was exposed to room air for 10 weeks after long-term heavy smoking).The expression of MMP-12 mRNA and protein in airway epithelium was detected by in situ hybridization and immunohistochemistry respectively.
RESULTS: Emphysema was seen in the lung tissue of every smoking rat,and was most severe in the long-term smoking group.Compared with control group,expression of MMP-12 in airway epithelium was remarkablely elevated in the long-term heavy smoking group, short-term heavy smoking group,long-term light smoking group and smoking cessation group(p<0.01). MMP-12 expression levels in long-term heavy smoking group were higher than that in other three smoking group(p<0.05).
CONCLUSION: Cigarette smoking is related to increased expression of MMP-12 in rats lung tissue.MMP-12 may play an important role in lung injury and airway remodeling in COPD.
CLINICAL IMPLICATIONS: This study provides new evidence supporting the hypothesis that imbalance in proteinase-antiproteinase play an important role in the pathogenesis of COPD.Targeting MMP-12 may provide novel treatment of COPD.
DISCLOSURE: Yi Ming Yuan, No Financial Disclosure Information; No Product/Research Disclosure Information