The Expression And Clinical Significance Of Oxidative Stress Markers In The Serum Of Patients With Stable Chronic Obstructive Pulmonary Disease

Objective:To detect the level of serum oxidative stress markers malondialdehyde(MDA),protein carbonyls(PC),8-hydroxy-2’-deoxyguanosine(8-OHdG)and total antioxidant capacity(TAC)of patients with stable chronic obstructive pulmonary disease(COPD),and explore the impacts of oxidant/antioxidant imbalance in the pathogenesis of COPD.Method:200 stable COPD patients(the COPD group)and 100 healthy individuals(the control group)were selected.Detected the concentration of serum MDA by thiobarbituric acid reactive substances assay,the level of serum PC by colorimetry,the level of serum 8-OHdG by double antibody sandwich ABC-ELISA,the level of serum TAC by o-phenanthroline colorimetric analysis.Tested the pulmonary function,collected the general information,and assessed the nutritional status with mini nutritional assessment(MNA)for each subjects.Results:(1)Classified the 200 stable COPD patients according to the degree of airflow limitation(GOLD classification):class I(mild)were 46 cases(23%),class Ⅱ(moderate)were 61 cases(30.5%),class Ⅲ(severe)were 72 cases(36%),class Ⅳ(extremely severe)were 21 cases(10.5%),the class Ⅲ was the most,class Ⅱ was the next,class Ⅳ was the least.(2)The level of serum MDA,PC and 8-OHdG in COPD group were significantly higher than in the control group,but the level of serum TAC were significantly lower than in the control group,all with statistically significant difference(P<0.01).(3)In the 200 COPD patients,the level of PC and 8-OHdG in smoking subgroup were significantly higher than in the no smoking subgroup,the difference was statistical significance between the two subgroups(P<0.05).(4)In the COPD group,the level of PC in the severe and extremely severe airflow limitation subgroups were significantly higher than in the mild and moderate airflow limitation subgroups,with statistically significant difference(P<0.01).(5)Multiple linear regression analysis showed that the levels of PC and 8-OHdG were negatively related with FEV1%in COPD patients,and the PC had greater impacts than 8-OHdG(β =-0.230,-0.219,P<0.01).(6)According to the MNA method,there were 106 cases(53%)with well-nourished,65 cases(32.5%)with risk of malnutrition,and 29 cases(14.5%)with malnutrition in the COPD group,of which,the malnutrition(risk)took 47%in those COPD cases.The levels of PC and TAC in the malnourished(risk)COPD subgroup were significantly higher than in the well-nourished COPD subgroup,with significantly statistical difference(P<0.05).Compared with the well-nourished COPD subgroup,the malnourished(risk)COPD subgroup were significantly lower in FEV1%and FEV1/FVC index.Multiple linear regression analysis showed that the level of PC and FEV1%in COPD group were associated with the MNA score,the level of PC was significantly negatively correlated with MNA score(β=-0.304,P<0.001),the FEV1%was significantly positively correlated with MNA score(β=0.367,P<0.001),and the impacts of FEV1%were greater than the level of PC.Conclusion:(1)The oxidation and antioxidant imbalance was obviously in the COPD patients.(2)Smoking would aggravate the protein carbonylation and DNA oxidative damage in COPD patients.(3)In stable COPD patients,protein carbonylation was related to the pathogenesis processes of COPD,the concentration of PC might be a sensitive monitoring index for the oxiative stress and the progress of COPD.(4)Oxidative stress was an influencing factor on pulmonary function,we might prevent the occurrence and development of COPD through avoiding the risk factors that enhanced the oxidative stress and using antioxidant therapy.(5)COPD patients tend to merge malnutrition,protein carbonylation and airflow limitation might be closely related to the malnutrition mechanism in COPD patients.