Antioxidant intervention of smoking-induced lung tumor in mice by vitamin E and quercetin

In the present study, Swiss mouse was used to examine the potential of quercetin and VE for prevention lung tumor induced by smoking.Our results suggest that the incidence of lung tumor and tumor multiplicity were 43.5% and 1.00 ± 0.29 in smoking group; Quercetin has limited effects on lung tumor prevention in this in vivo model, as measured by assays for free radical scavenging, reduction of smoke-induced DNA damage and inhibition of apoptosis. On the other hand, vitamin E drastically decreased the incidence of lung tumor and tumor multiplicity which were 17.0% and 0.32 ± 0.16, respectively (p < 0.05); and demonstrated prominent antioxidant effects, reduction of DNA damage and decreased cell apoptosis (p < 0.05). Combined treatment with quercetin and VE in this animal model did not demonstrate any effect greater than that due to vitamin E alone. In addition, gender differences in the occurrence of smoke induced-lung tumor and antioxidant intervention were also observed.We conclude that VE might prevent lung tumor induced by smoking in Swiss mice.Smoking, including second-hand smoking, poses a serious threat to public health. Smoke induced-lung tumor has become one of the malignancies with highest incidence and mortality worldwide [1-3]. Therefore, increasing attention has been paid to searching for effective approaches to the prevention and treatment of smoke-induced lung tumor, including the use of antioxidants. Although the Beta-Carotene Tumor Prevention Study Group demonstrated that beta-carotene may actually promote the development of lung tumor in male smokers rather than prevent the disease [4], the majority of epidemiological findings support the preventive effects of antioxidants, including quercetin and vitamin E (VE), on smoke-induced lung tumor [5-11]. Moreover, in vitro studies have shown that quercetin and VE can prevent the proliferation, invasion, and metastasis of tumor cells and promote the apoptosis of lung tumor cells [12-20]. However, to our kno