SLPI Inhibited The Expression Of Inflammation Mediators In NHBE Cells Induced By Cigarette Smoke Extract

Objective Airway epithelial cells are the first barrier by whichlung resist injuries coming from outer environment. Some physical andchemical factors such as pathogenic microorganism and various particlesin polluted air of outer environment can stimulate airway epithelial cellsand finally result in its functions damages, which are initial pathologicchanges of some chronic airway diseases such as chronic obstructivepulmonary diseases. Smoking is an important dangerous factor of chronicobstructive pulmonary diseases (COPD). Smoking and matrixmetalloproteinase-9 (MMP-9) with IL-8 beget COPD happening.Secretory leukocyte proteinase inhibitor (SLPI) is important to protect thelocal airway. SLPI inhibited the expression of MMP-9 and IL-8 innormal human bronchial epithelial cells induced by cigarette smokeextract (CSE) through the following experiments. Discussing the partmechanism of SLPI how to protect the local airway of chronic airwaydiseases would afford much more experiments basis of COPD clinictreating.Methods The experiment was divided into four groups, includingcontrol group, CSE group, SLPI group and SLPI+CSE group. NHBEcells were cultured in vitro. It was treated with different time of CSE anddifferent concentration of SLPI. The following assays were carried out. The expression levels of IL-8 in NHBE cells supernatant was examinedby ELISA. The expression of MMP-9 protein in NHBE cells wasevaluated by using immuno-cytochemical stain method.The content ofMMP-9 mRNA was determined by reverse transcription -polymerasechain reaction(RT-PCR) method and image analysis.Results 1 A small quantities of MMP-9 and IL-8 expression wasobserved in control group NHBE cells.2 The expression of MMP-9 andIL-8 in NHBE cells of CSE group was highly than that of the other threegroups. After exposure to different time of CSE, The expression levels ofMMP-9 and IL-8 relied directly on CSE exposure time within certainlimits. A climax expression was observed at the time of 24 hours beingexposured with CSE. But subsequently the tendency descended.3 SLPIdecreased the expression levels of MMP-9 and IL-8. The expressionlevels of MMP-9 and IL-8 in SLPI group NHBE cells were lower thanthat of the other three groups. Within certain limits the inhibiting effectdepended on SLPI concentrations directly. When NHBE cells wereexposured at the 10ug/ml SLPI concentration, the inhibiting effect wasstrongest. 4 The expression levels of MMP-9 and IL-8 in SLPI+CSEgroup were higher than that of the control group and SLPI group. But itwere lower than that of CSE group.Conclusion 1. CSE could increase the expression levels ofMMP-9 and IL-8 in NHBE cells. 2. SLPI could inhibit the expression levels of MMP-9 and IL-8 in NHBE cells.3. SLPI could inhibit theexpression levels of MMP-9 and IL-8 in NHBE cells induced byCigarette smoking extract.