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Int J Clin Exp Pathol 2013;6(8):1523-1531

Original Article
Tea polyphenols prevent lung from preneoplastic lesions and effect p53 and bcl-2 gene
expression in rat lung tissues

Qihua Gu, Chengping Hu, Qiong Chen, Ying Xia

Department of Respiratory Medicine, Xiangya Hospital Affiliated to Central South University, Changsha City, Hunan, 410008, PR China

Received May 26, 2013; Accepted June 21, 2013; Epub July 15, 2013; Published August 1, 2013

Abstract: Lung cancer is one of the cancers that have the highest incidence and the highest mortality rate, and it is of great interest to identify
ways to prevent its occurrence. We had established an animal model by using 3,4-benzopyrene intra-pulmonary injection in our previous study,
and had observed that the rats lung carcinoma incidence and multiplicity were significantly reduced by green tea administration. This study
further investigated the effect of tea polyphenols on rat lung preneoplastic lesions using the lung carcinoma model established by 3,4-
benzopyrene intra-pulmonary injection. Sprague–Dawley rats of the same age were randomly divided into 10 groups and treated with 3,4-
benzopyrene by intra-pulmonary injection. Five groups were given 0.3% solution of tea polyphenols (equivalent to 1.2% of green tea) in drinking
water, while the other 5 groups were given pure drinking water. The rats were sacrificed at 0, 1, 4, 8 and 16 weeks after carcinogen treatment. In
the control groups of rats, local bronchial inflammation were observed at 1 week after 3,4-benzopyrene treatment. From 4 weeks to 16 weeks
after carcinogen treatment, hyperplasia, cell hyperproliferation, heterogeneity were observed in the bronchial epithelium. Meanwhile, the
expression of p53 mRNA and protein, as well as the level of bcl-2, increased in the bronchial epithelial lesion. Tea polyphenols treatment
significantly alleviated the bronchial epithelial lesions. At the same time, tea polyphenols treatment enhanced p53 expression, but reduced bcl-
2 expression. These results indicated that tea polyphenols may have preventive effect against lung preneoplasm lesions, possibly through
regulating the expression of some critical genes such as p53 and bcl-2. (IJCEP1305033).

Keywords: Lung cancer, cancer prevention, tea polyphenols, p53 gene, bcl-2 gene

Address correspondence to: Dr. Qihua Gu, Department of Respiratory Medicine, Xiangya Hospital Affiliated to Central South University,
Changsha City, Hunan, 410008, PR China. E-mail: guqh06@163.com