Fan Zhou1, Ting Shen2, Ting Duan3, Yu-Ying Xu3, Soo Chin Khor3, Jin Li3, Juan Ge3, Yi-Fan Zheng3, Stephen Hsu4, Jamie DE Stefano5, Jun Yang6, Li-Hong Xu7, Xin-Qiang Zhu8. 1. Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, Zhejiang, P.R. China Minhang District Center for Disease Control and Prevention of Shanghai, Shanghai, P.R. China. 2. Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, Zhejiang, P.R. China Xihu District Center for Disease Control and Prevention, Hangzhou, Zhejiang, P.R. China. 3. Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, Zhejiang, P.R. China. 4. Department of Oral Biology and Maxillofacial Pathology, Georgia Health Sciences University, Augusta, GA, U.S.A. 5. Department of Periodontics, Georgia Regents University, Augusta, GA, U.S.A. 6. Department of Toxicology, Hangzhou Normal University School of Public Health, Hangzhou, Zhejiang, P.R. China. 7. Department of Biochemistry and Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China zhuxq@zju.edu.cn xulihong@zju.edu.cn. 8. Department of Toxicology, Zhejiang University School of Public Health, Hangzhou, Zhejiang, P.R. China zhuxq@zju.edu.cn xulihong@zju.edu.cn.
Abstract
BACKGROUND: The purpose of the present study was to compare the antioxidant potential of lipophilic tea polyphenols (LTP) against the one of naturally-occurring water-soluble green tea polyphenols (GTP) in a two-stage model of diethylnitrosamine (DEN)/phenobarbital (PB)-induced hepatocarcinogenesis in Sprague-Dawley rats. MATERIALS AND METHODS: GTP/LTP was given 5-times weekly by oral gavage with tea polyphenols equivalent to 0-, 40- and 400-mg/kg of body weight/day. GTP/LTP treatment was started 2 weeks prior to the initiation of DEN and continued for 30 weeks. RESULTS: Histopathological and electron microscopic examination of liver tissue confirmed the protective effect of LTP on DEN/PB-induced liver damage and pre-carcinogenesis. LTP treatment significantly increased total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) activity in liver tissues. Immunohistochemical detection of cellular nuclear factor erythroid-2-related factor-2 (Nrf2) and peroxiredoxin-6 (P6) indicated a down-regulation in Nrf2 and up-regulation of P6 expression in the liver of LTP-supplemented rats. CONCLUSION: The present study provides evidence for the first time, that LTP exerts significant antioxidant effects on DEN/PB-induced liver damage and hepatocarcinogenesis through elevating T-AOC levels, enhancing GSH-Px activity and inducing P6 expression in rat liver tissues.
BACKGROUND: The purpose of the present study was to compare the antioxidant potential of lipophilic tea polyphenols (LTP) against the one of naturally-occurring water-soluble green tea polyphenols (GTP) in a two-stage model of diethylnitrosamine (DEN)/phenobarbital (PB)-induced hepatocarcinogenesis in Sprague-Dawley rats. MATERIALS AND METHODS:GTP/LTP was given 5-times weekly by oral gavage with tea polyphenols equivalent to 0-, 40- and 400-mg/kg of body weight/day. GTP/LTP treatment was started 2 weeks prior to the initiation of DEN and continued for 30 weeks. RESULTS: Histopathological and electron microscopic examination of liver tissue confirmed the protective effect of LTP on DEN/PB-induced liver damage and pre-carcinogenesis. LTP treatment significantly increased total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) activity in liver tissues. Immunohistochemical detection of cellular nuclear factor erythroid-2-related factor-2 (Nrf2) and peroxiredoxin-6 (P6) indicated a down-regulation in Nrf2 and up-regulation of P6 expression in the liver of LTP-supplemented rats. CONCLUSION: The present study provides evidence for the first time, that LTP exerts significant antioxidant effects on DEN/PB-induced liver damage and hepatocarcinogenesis through elevating T-AOC levels, enhancing GSH-Px activity and inducing P6 expression in rat liver tissues.
Authors: Piotr Olcha; Anna Winiarska-Mieczan; Małgorzata Kwiecień; Łukasz Nowakowski; Andrzej Miturski; Andrzej Semczuk; Bożena Kiczorowska; Krzysztof Gałczyński Journal: Int J Mol Sci Date: 2022-06-16 Impact factor: 6.208