Effects of smoking cessation on expressions of nuclear factor-κB, matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in airway epithelial cells of smoking rats

Objective To investigate the effects of smoking and smoking cessation on airway inflammation and remodeling in chronic obstructive pulmonary diseases through detecting mRNA and protein expressions of nuclear factor-κB (NF-κB), cell matrix metalloproteinase-9 (MMP-9) and cellular tissue inhibitor of metalloproteinase-1 (TIMP-1) in airway epithelial cells of smoking and smoking cessation rats. Methods Twenty-four male Wistar rats were randomly divided into control group, smoking group and smoking cessation group,eight in each group. Hybridization in situ and immunohistochemistry were used to detect mRNA and protein expressions of NF-κB, MMP-9 and TIMP-1 in airway epithelial cells of rats. Results ① Compared with control group (0.29 ± 0.06,0.29±0.06), mRNA and protein expressions of NF-κB in smoking group (0.45±0.04,0.41±0.03) and smoking cessation group (0.40±0.05,0.37±0.03) were higher (all P＜0.05). The mRNA and protein expressions of NF-κB in smoking cessation group were lower than those in smoking group (all P ＜0.05). ②Compared with control group (0.30±0.06,0.30±0.06) ,mRNA and protein expressions of MMP-9 in smoking group (0.52±0.03,0.51±0.07) and smoking cessation group (0.38±0.03,0.33±0.02) were higher (all P＜0.05). The mRNA and protein expressions of MMP-9 in smoking cessation group were lower than those in smoking group (all P＜0.05). ③Compared with control group (0.26±0.04, 0.26±0.04), mRNA and protein expressions of TIMP-1 in smoking group (0.49±0.05,0.37±0.03) and smoking cessation group (0.42±0.04,0.35±0.03) were higher (all P ＜0.05). The mRNA and protein expressions of TIMP-1 in smoking cessation group were lower than those in smoking group (all P ＜ 0.05). ④ Compared with control group (1.00±0.02,1.00±0.02), MMP-9/TIMP-1 mRNA and protein expressions were larger than one in smoking group (1.07±0.14, 1.37±0.19), and less than one in smoking cessation group (0.92±0.13,0.94±0.10) (all P ＜0.05). ⑤The mRNA and protein expressions of NF-κB and MMP-9in each group were positively correlation (r=0.87,0.66,all P ＜0.05). Conclusions In airway epithelial cells of smoking rats, mRNA and protein expressions of NF-κB, MMP-9 and TIMP-1 increase, and MMP-9/TIMP-1 is larger than one. After stoping smoking, mRNA and protein expressions of NF-κB,MMP-9 and TIMP-1 decrease, and MMP-9/TIMP-1 is less than one. This experiment explains that smoking can cause airway inflammation and remodeling, smoking cessation can reduce airway inflammation and remodeling.