The Correlation Investigation Between The Assay Of 8-isoprostane And Interleukin-8 In Plasma In The Pathogenesis Of Chronic Obstructive Pulmonary Disease(COPD)

Obiective: Chronic obstructive pulmonary disease (COPD) is a disease with high morbidity and mortality. Recent data regarding pathogenesis are confusing unclear. The persistent chronic inflammatory response in lung and oxidative stress may play an important role in the pathogenetic mechanisms underlying COPD. 8-isoprostane is one of markers of oxidative stress, and interleukin -8(IL-8) is an important neutrophil chemotactic factor. In this study, the levels of 8-isoprostane and IL-8 in serum were assayed. The correlation of oxidative stress burden, inflammatory response and airflow limitation in patients with COPD were investigated.Methods: 1. The lung function of 20 patients with COPD and 40 healthy volunteers which including 16 healthy smokers and 24 healthy non-smokers were tested by profile pulmonary function system 2. Venous samples of COPD in severe exacerbation and stable stage, and control group were collected. The levels of free 8-isoprostane and IL-8 in serum were assayed. The free 8-isoprostane in serum was measured by enzyme immunoassay. The IL-8 in serum was assayed by enzyme-linked immunoadsordent assay.Results: Significantly decreased FEV1% and FEV1/FVC %were shown in COPD patients, as compared to the healthy control group [(50.1±17.27)vs.(106.0±20.82), P＜0.01 and (56.2±10.31) vs.(83.4±6.34),P＜0.01, respectively]. In severe exacerbation of COPD, the level of free 8-isoprostane was significantly higher than the stable stage of COPD (5.42±2.416pg/ml, 3.30±2.267pg/ml, respectively, P＜0.01). And the level of IL-8 was significantly higher than the stable stage of COPD {(657.3222±723.0761)pg/ml, [M 125.1124, 95%CI (13.7871±792.894)]pg/ml, respectively, P＜0.01}. In healthy smokers, the level of free 8-isoprostane in serum was higher than healthy non-smokers [(5.72±2.195)pg/ml,(4.3±1.964)pg/ml, respectively, P＜0.05]. And the level of IL-8 was significantly higher than healthy non-smokers {(410.8701±353.0703)pg/ml, [M 95.81700,95%CI (59.3424～833.328)] pg/ml, respectively, P＜0.01}The level of free 8-isoprostane in serum had no correlation with FEV1% and FEV1/FVC in patients with COPD(r=-0.076 and-0.046,respectively, P＞0.05). The level of IL-8 in serum had no significant correlation with FEV1% and FEV1/FVC in patients with COPD(r=-0.426 and -0.049, respectively, P＞0.05). In severe exacerbation stage and stable of COPD, the significant correlation between IL-8 and 8-isoprostanewas not found(r=0.313 and 0.13, respectively, P＞0.05). In healthy smokers, the level of IL-8 in serum had no significant correlation with free 8-isoprostane(r=0.132, P＞0.05).Conclusion:1. A significant air flow limitation that is not fully reversible occurred in COPD.2. The level of 8-isoprostane was greatly increased in severe exacerbation of COPD. This indicates that the system oxidative burden was greatly increased in the stage, and oxidative stress may play an important role in the pathogenesis of COPD.3. In smokers, 8-isoproatane and IL-8 were higher than in non-smokers. These indicate that cigarette smoking can increase the level of oxidants, which may induce and enhance oxidative stress; meanwhile oxidative stress may activate inflammatory cells.4. In severe exacerbation of COPD, IL-8 was increased compared with the stable stage. This indicates that the system inflammatory response was enhanced in severe exacerbation of COPD. The activated inflammatory cells may take part in the loss of lung function and the system effects such as weight loss in COPD; the cytokines and oxidative stress may also attend the reaction.