Abstract: The objective of the study is to investigate the intervention effects of green tea polyphenols (GTP) on oxidative stress induced by passive smoking in mice lung and its possible mechanisms. Forty healthy Kunming mice (female) were randomly divided into 4 groups including normal control group (C), passive smoking model group (M), GTP treated group 1 (GTP1, 100βmg·kg^-1) and GTP treated group 2 (GTP2, 200βmg·kg^-1) respectively (n=10). All mice were killed after treating with GTP for 12 weeks. The morphology and quality of lung, the oxidative stress of serum and inflammatory level were determined. The mRNA expression levels of inflammation-related genes including interleukin 6 (IL-6), interleukin 33 (IL-33), tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) were measured by fluorescence quantitative PCR. Compared to M group, the life quality and pulmonary morphology of mice in GTP1 and GTP2 were significantly improved, and T-SOD and GSH-Px activities in serum were also significantly enhanced. But MDA, IL-6 and TNF-α levels in serum were decreased significantly. The mRNA expressions of IL-6, IL-33, TNF-α and IL-1β were also declined in GTP groups, which were clearly dose-dependent. These results showed that GTP could protect lung against damage of passive smoking and remain the integrity of lung tissues by inhibiting inflammatory cytokine expression and improving the antioxidant capacity.

Key words: green tea polyphenols, passive smoking, lung tissue, oxidative stress