Regulation Of Nuclear Factor-kappa B On Intercellular Adhesion Molecule-1 Induced By Cigarette Smoking

Objective: To explore the regulation of nuclear factor-kappa B (NF-кB) on smoking-induced intercellular adhesion molecule-1 (ICAM-1 ) by observing the activation of NF-кB and expression of ICAM-1 induced by cigarette smoke extract (CSE) only and with pyrrolidine dithiocarbamate (PDTC) in mouse macrophages.Methods: The experiments were conducted in two sections. 1. Immunocytochemical technique was used to examine NF-кB activation and ICAM-1 protein expression in different times after CES and lipopolysaccharide (LPS) inducing in mouse macrophages (Ana-1). The test was repeated three times; 2. Immunocytochemical technique and reverse transcription-polymerase chain reaction (RT-PCR) were used to examine the effects of NF-кB specific inhibitor, PDTC and dexamethasone (DEX) on NF-кB activation and ICAM-1 expression induced by CSE in mouse macrophages. The test was repeated three times.Results: 1.(1) After incubated 30 min with stimulators, the percentage of NF-KB nuclear stain positive cells in CES group (41.80%±4.44%) and LPS group (37.59%±3.94%) was significantly higher than that in the control group (8 .66%±1.22%), P<0.01 respectively. NF-кB activation reached the peak value after stimulated for 30 min and 3 hours in LPS group (37.59%±3.94%) and CSE group (49.20%±3.37%) respectively, and decreased after 6 hours, but it was higher than that in the control group, P<0.01 respectively. The percentage of NF-кB nuclear stain positive cells in CES group (8.35%±1.15%)was similar with control group (7.81%±1.21%) after incubated for 24h, P>0.05, whereas that of LPS group (21.34%±2.21%) was higher than control group. (2) After incubated with stimulators, the percentage of ICAM-1 expression positive cells in CES group and LPS group increased little by little and was significantly higher than that in the control group (8.26%±1.52%), P<0.01 respectively. Both of their ICAM-1 expression reached the peak after stimulated for 12 hours (41.61%±4.44%, 38.27%±3.22%, 49.68%±2.52% and 24.54%±3.38%), and began to decrease in 24 hours . (3) The percentage of NF-кB nuclear positive cells was significantly correlated with that of ICAM-1 expression positive cells, r=0.941, P<0.01. 2. (1) The percentage of NF-кB nuclear stain positive cells, expression of ICAM-1 mRNA and its protein stain positive cells percentage were significantly decreased in CES+PDTC group (17.89%±2.62%, 0.976±0.052 and 18.42%±1.06%) and CSE+DEX group (12.72±1.10%, 1.067±0.041 and 27.76%±2.06%) as compared with CSE group (41.50%±1.30%, 1.336±0.054 and 43.02%±2.37%), P<0.01 respectively. (2) The percentage of NF-кB nuclear positive cells was significantly correlated with the expression of ICAM-1 mRNA and the percentage of its protein expression positive cells, r= 0.789 and 0.833, P<0.01 respectively.Conclusion: Cigarette smoking-induced expression of intercellular adhesion molecule-1 is regulated by NF-кB in mouse macrophages, which is probably the mechanism of development of cigarette smoking-induced chronic inflammation in airway. Dexamethasone can suppress the activation of NF-кB and expression of ICAM-1.