Effects Of Carbon Dioxide On The Expression Of Some Inflammatory Factors And IgA In Lung And Trachea Of Mice

CO₂ is an important factor affecting the respiratory health of animals and humans.To explore the effecting mechanism of CO₂ on animal respiratory system,40 mice were randomly divided into four groups with ten in each group and were fed under different concentration of CO₂ for 14 d.In group 1,the mice were fed in the ordinary air condition in the room.In Group 2,group 3,and group 4,animals were fed at a concentration of 1500 mg/m³,2500 mg/m³ and 3500mg/m³ of CO₂,respectively.After feeding for 14 d,the samples of mouse trachea and lungs were taken into Bouin’s solution for 24 h to be fixed.Distribution of immunoreactive positive materials with interleukin-6（IL-6）,tumor necrosis factor alpha（TNF-α）,interleukin-1β（IL-1β）and Immunoglobulin A（IgA）in the pulmonary respiratory portion and tracheal wall were observed by histological and immunohistochemical staining techniques.Their expression amount were analyzed through measuring the mean greay values in the microphotos using the image analysis soft of ImageJ.The results showed that the IL-6 immunoreactive positive materials were mainly observed in the mucous layer of the pulmonary terminal bronchioles,alveolar epithelium,mucous layer of tracheal wall.The average gray values in the lungs were157.12±9.04,158.50±11.44,165.91±9.11 and 170.86±9.08,respectively.The average gray values in the tracheal wall was 143.18±7.17,159.48±11.93,160.92±11.93 and169.66±9.67,respectively.The mean gray value was highest in group 4 and significantly higher than the other 3 groups（p<0.05）.The TNF-αimmunoreactive positive materials were mainly observed alveolar septum respiratory,typeΙΙalveolar epithelial cells,and the epithelial cells in the tracheal wall.The average gray value in the lung respiratory part was 150.58±7.90,156.21±9.67,164.07±9.55 and168.00±12.20,and the average gray value in the tracheal wall was 145.20±13.00,150.35±7.72,156.45±12.85 and 160.75±14.82.The mean gray value in the lung respiration and tracheal wall was highest in group 4 and significantly higher than group 1,group 2,and group 3（p<0.05）.The IL-1βimmunoreactive positive materials were mainly observed in alveolar duct,lung fibroblasts,and epithelial in the mucosa of the tracheal wall.The average gray value of lung respiratory part was 143.91±9.63,147.62±10.21,155.87±8.90 and 168.89±10.53,and the gray value of tracheal wall was 140.03±11.31,155.27±12.24,157.61±13.08 and 159.05±14.56.The gray value of IL-1βin lung respiration and tracheal wall was the highest in group 4,and significantly higher than group 1,group 2 and group 3（p<0.05）.The IgA immunoreactive positive materials were mainly observed in respiratory terminal bronchioles,type II alveolar cells and in the submucosa of the tracheal wall.The average gray values of lung respiration were 140.85±9.09,141.73±10.05,142.05±11.73 and 144.73±12.93,respectively.The gray values of tracheal wall were145.03±8.91,146.27±9.09,148.61±10.65 and 150.05±13.35,respectively.The differences between the tissues were not significant（p>0.05）.It indicated that with the increase of concentration of CO₂,the expression levels of cytokines IL-6,TNF-αand IL-1βin the lungs and tracheal walls increased.Higher concentration of CO₂ in the environment cause lungs and tracheal wall the lungs of mice to be inflammatory state.There is no significant effect of concentration of CO₂on secretory IgA in the lungs and tracheal walls.