Key Factor Of Pneumonia’s Occurrence And Aggravation:Oxidative Stress-DNA Damage

Objective:To study the degree of oxidative stress, the capacity of antioxidant and the corresponding changes of cell DNA damage in pneumonia patients; to explorer the role of oxidative stress-DNA damage in pneumonia. Methods:Collected67pneumonia patients in Respiratory Medicine Department of Affiliated Hospital of Luzhou Medical College from June2011to March2012, including35pneumonia patients,32severe pneumonia patients, recruited32healthy volunteers as control group, obtained2ml venous blood from64patients and32volunteers respectively, the3volunteers and remaining3pneumonia patients were inspected by bronchoscopy and airway tissue biopsy, observed airway inflammatory cells infiltrated with light microscopy and airway tissue ROS staining with ordinary fluorescent microscopy; Measured ROS to detect the degree of human PBMC oxidative stress by confocal fluorescent microscopy and full wave-length spectrophotometer in64patients and32volunteers respectively; Measured SOD to detect the level of anti-oxidant in serum by full wave-length spectrophotometer; detected cell DNA damage of human PBMC in Comet assay by ordinary fluorescent microscopy. Results:1.The observation of Light microscopy: frozen section of airway tissue by HE staining, there were a few inflammatory cells infiltrated in bronchial airway tissue in normal control group; there were a lot of inflammatory cells were infiltrated in bronchial airway tissue in pneumonia group.2.The observation of ordinary fluorescent microscopy:frozen sections of airway tissue stained by ROS probe (DHE), pneumonia groups’red fluorescent intensity were stronger than normal control group.3.ROS measured by confocal fluorescent microscopy:the average fluorescent intensity of each group, pneumonia group(3.308±0.240) and severe pneumonia group(6.628±0.349) were higher than normal control group(1.505±0.352)(P<0.01), severe pneumonia group was the highest (P<0.01).4. detection of PBMC DNA damage in comet assay (COMET SOP):The cells’ average tail length of each group, pneumonia group(6.783±5.015) and severe pneumonia group(30.363±7.436) were higher than normal control group(0.095±0.123)(P<0.05), severe pneumonia group was the highest (P<0.01).5.serum SOD measured by full wave-length spectrophotometer:the average optical density of each group, pneumonia group(0.225±0.030) and severe pneumonia group(0.159±0.033) were lower than normal control group (0.456±0.024)(P<0.01), severe pneumonia group was the lowest (P<0.01).6.ROS measured by full wave-length spectrophotometer:the average optical density of each group, pneumonia group (0.913±0.065) and severe pneumonia group (1.260±0.023) were higher than normal control group (0.390±0.031)(P<0.01), severe pneumonia group was the highest(P<0.01).7.Correlative analysis:(1)There were significantly positive correlations between ROS average fluorescent intensity and cells’average tail length(r=0.878,P<0.01,n=24);(2)There were significantly negative correlations between ROS average fluorescent intensity and SOD average optical density(r=-0.847,P<0.01,n=24);(3)There were significantly positive correlations between ROS average optical density and cells’ average tail length(r=0.815,P<0.01,n=24);(4)There were significantly negative correlations between ROS average optical density and SOD average optical density(r=-0.952,P<0.01,n=24). Conclusion:Oxidative stress-DNA damage maybe one of the important reasons of pneumonia’s occurrence and aggravation.