Oxidative stress and inflammatory changes in the lung caused by cigarette smoking exposure in mice and the effect of smoking cessation / 安徽医科大学学报

ABSTRACT

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.