Roles Of Inflammatory Factors In Lung Injury Induced By Cigarette Smokes

Objective: The research aimed at observing expressions of several inflammatory factors and pathological diagnosis in lung injury induced by cigarette smoking, then we discussed the relationship between cytokines and pathological diagnosis of lung, which provided theoretical and practical bases to the lung injury induced by cigarette smoking.Materials and methods: The mice were divided into 4 groups, normal group(NC), low-dose group(L), middle-dose group(M) and high-dose group(H). We controlled the time of exposure to cigarette smokes strictly, 10/20/40 min respectively. Then we detected the inflammatory reactions and pathological diagnosis in signal exposure group,long-term exposure group and quit-smoking group. We executed mice 6/24/72h after single exposure; mice in long-term exposure group were killed after 3/15/30/90/180d's exposure respectively; mice in smoking-abatement group were killed 15/30/60d after 180d-exposure. The indices included weights of body and many organs, blood cells'numbers, biochemical indices and cytokines in serum, lung homogenate and bronchoalveolar lavage fluid (BALF), pathological diagnosis of lungs, the changes of collagen/fiber and 8-OH-dG expressions.Results:1. Comparing with NC group's, mice in single exposure group showed:(1)The body weight and coefficients of lung, liver and brain had no significant change;(2)WBC increased significantly, while RBC increased at first and decreased later;(3)The total cell number of BALF in exposure groups increased obviously;(4)Several cytokines in lung homogenate such as MIP-1α, Rantes, MCP-1, KC, GM-CSF, IFN-γ, TNF-α, IL-1βshowed a―increased firstly and decreased later‖tendency. 2. Comparing with NC group's, mice in long-term exposure group showed:(1)The increase of body weight was inhibited obviously;(2)The coefficients of heart and brain increased significantly, while the liver coefficient lowered;(3)The lung of cigarette groups revealed a pathological change distinctly;(4)The expressions of ALP, ACP, LDH in serum and so on changed;(5)WBC increased firstly and then decreased, while RBC showed the opposite tendency;(6)The changes of several cytokines including MIP-1a, KC, GM-CSF, IFN-γ, TNF-α, IL-1, IL-4,IL-5 and IL-6 had positive correlation with the time and the dose of exposure to cigarette smokes.3. Comparing with 180d-exposure group's, mice which stopped smoking showed:(1)Body weight increased obviously;(2)The coefficients of organs had no distinct changes comparing with these of normal group;(3)The degree of pathological changes had decreased;(4)The numbers of WBC and RBC were close to the normal level;(5)Expressions of cytokines like MIP-1a, Rantes, MCP-1, KC, GM-CSF, IFN-γand TNF-αdeclined significantly.Conclusion: Exposure to cigarette smokes led to increase of inflammatory reactions in lung tissue, which showed a―dose-effect‖relationship; long-term exposures to different doses of cigarette smokes had different negative influences on lung tissue; when the mice stopped passive smoking, the lung injury and inflammatory reaction released significantly.