烟雾暴露小鼠肺部氧化应激与炎症的变化及戒烟的影响

Oxidative stress and inflammatory changes in the lung caused by cigarette smoking exposure in mice and the effect of smoking cessation

目的观察烟草暴露小鼠肺部氧化应激状态变化与炎症因子的关系及戒烟对其的影响。方法50只雄性Balb/c小鼠按随机数字表法分为对照组、烟雾暴露组、戒烟组。戒烟组小鼠烟雾暴露16周后戒烟,戒烟4、8、12周时处死小鼠留取支气管肺泡灌洗液(BALF)及肺组织标本。采用HE法观察小鼠肺组织病理学形态改变,测量肺平均内衬间隔和平均肺泡数,收集BALF进行细胞计数,羟胺法测定肺组织匀浆中超氧化物歧化酶(SOD)活力,TBA法测定肺匀浆中丙二醛(MDA)水平,ELISA法测定BALF和肺匀浆中白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)的浓度。结果与对照组比较,烟雾暴露组小鼠出现明显的肺气肿变化,BALF中炎症细胞显著增多(P<0.05),戒烟后明显减少(P<0.05);肺组织匀浆中SOD活力和MDA水平增高(P<0.05),戒烟后逐渐下降。烟雾暴露组小鼠BALF、肺组织匀浆中IL-8和TNF-α浓度显著增高(P<0.05),戒烟后明显降低,并随戒烟时间延长更加明显,但未降至正常水平。SOD活力和MDA水平与炎症因子之间呈显著正相关性。结论吸烟可以导致小鼠肺部氧化应激异常和气道炎症,戒烟可减轻氧化应激和气道炎症,但未能恢复到完全正常,炎症持续存在。

Objective To observe the changes of pulmonary oxidative stress after cigarette smoking exposure,its re-lationship with inflammatory cytokines,and the effects of smoking cessation. Methods Fifty male BALB / c mice were randomly divided into the smoke exposure group,smoke cessation group,and the controls. Mice in smoke cessation group were exposed to cigarette smoking for 16 weeks. On 4,8,and 12 week after smoking cessation mice were executed and the bronchoalveolar lavage fluid（BALF）and lung tissue were collected. The morphologi-cal alternations of lung tissue were observed. Mean length of interval and mean alveolar number were measured. Total cell numbers in BALF were counted. Superoxide dismutase（SOD）activity was measured with hydroxylamine method,malondialdehyde（MDA）level was measured with TBA method. The levels of pulmonary interleukin-8 （IL-8）and tumor necrosis factor-α（TNF-α）in BALF and lung tissue homogenate were measured with ELISA. Re-sults Compared with the mice in the controls,emphysematous changes were remarkable in the lung of cigarette ex-posed mice,the total cell numbers in BALF were increased significantly（P 〈 0. 05）and reduced gradually after smoking cessation（P 〈 0. 05）. SOD and MDA levels increased remarkably in the cigarette exposure group（P 〈0. 05）,and declined gradually after smoking cessation. The levels of IL-8 and TNF-α in BALF and lung tissue ho-mogenate in the smoke exposure group increased significantly（ P 〈 0. 05）,and lowered time-dependently after smoking cessation,but not reached to normal level even 12 weeks after smoking cessation. SOD and MDA levels were positively correlated with the cytokine changes. Conclusion Abnormal oxidative stress in the airways caused by cigarette smoking exposure was merely partially reversed after smoking cessation. And the inflammation remains persistent concomitantly.