Inhibition of N-nitrosomethylbenzylamine-induced esophageal tumorigenesis in rats by green and black tea.
Inhibition of N-nitrosomethylbenzylamine-induced esophageal tumorigenesis in rats by green and black tea.
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DOI：
10.1093/carcin/16.9.2143
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发表时间：
1995-09
期刊：
影响因子：
4.7
通讯作者：
Z. Y. Wang;Li Dong Wan;Mao-jung Lee;Chi-Tang Ho;Mou-tuan Huang;A. Conney;Chung S. Yang
中科院分区：
文献类型：
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作者：
Z. Y. Wang;Li Dong Wan;Mao-jung Lee;Chi-Tang Ho;Mou-tuan Huang;A. Conney;Chung S. Yang
在这项研究中，我们研究了绿茶和红茶在致癌物治疗期间或之后对雄性Sprague-Dawley大鼠食道肿瘤发生的影响。n -亚硝基甲基苄胺（NMBzA） （2.5 mg/kg, s.c，每周2次）给药5周；初始剂量NMBzA 39周后，65%的大鼠出现食道肿瘤，平均每只大鼠1.4 +/- 0.3个肿瘤。在nmbza治疗期间，以0.6%的脱咖啡因绿茶（DGT）或脱咖啡因红茶（DBT） （6 mg茶固体/ml）作为唯一饮用液体的大鼠组中，食道肿瘤的发病率和多样性减少了约70%。在NMBzA治疗期后给予茶制剂，食道乳头状瘤的发病率和多样性降低了约50%。在致癌物治疗期后喝红茶的老鼠，每个肿瘤的体积要小得多。在第二组实验中，NMBzA以3.5 mg/kg （s.c，每周2次）的剂量给药，连续5周；16周后，肿瘤发生率为82%，肿瘤多样性为6.7 +/- 1.2个。在NMBzA治疗期后接受0.9%常规绿茶（RGT）或DGT的大鼠组，肿瘤多样性降低了约55%。在接受0.9% RGT的大鼠中，每个肿瘤的体积减少了约60%。组织学分析表明，RGT和DGT均可降低食管癌的发生率和多样性。在大鼠中测定了由于喝茶引起的血液和尿液中绿茶多酚的水平，这些水平与人类喝茶后的水平相当。上述结果表明，绿茶和红茶均能抑制NMBzA在致癌物治疗期间的致瘤作用以及随后对食管肿瘤发生重要的分子事件。
In this study, we investigated the effects of green tea and black tea, when given either during or after carcinogen treatment, on esophageal tumorigenesis in male Sprague-Dawley rats. Rats were treated with N-nitrosomethylbenzylamine (NMBzA) (2.5 mg/kg, s.c., twice weekly) for 5 weeks; 39 weeks after the initial dose of NMBzA, 65% of the rats had esophageal tumors with an average of 1.4 +/- 0.3 tumors per rat. In the groups of rats receiving 0.6% of decaffeinated green tea (DGT) or decaffeinated black tea (DBT) (6 mg tea solids/ml) as the sole source of drinking fluid during the NMBzA-treatment period, esophageal tumor incidence and multiplicity were reduced by approximately 70%. When the tea preparations were given after the NMBzA treatment period, the esophageal papilloma incidence and multiplicity were reduced by approximately 50%. The volume per tumor was much smaller in rats that received black tea after the carcinogen treatment period. In a second experiment, NMBzA was given to rats at a dose of 3.5 mg/kg (s.c., twice weekly) for 5 weeks; after 16 weeks, the tumor incidence was 82% and tumor multiplicity was 6.7 +/- 1.2 tumors per rat. In the groups of rats receiving 0.9% regular green tea (RGT) or DGT after the NMBzA treatment period, tumor multiplicity was decreased by > 55%. The volume per tumor was reduced by approximately 60% in the rats receiving 0.9% RGT. Histological analysis indicated that both the incidence and multiplicity of esophageal carcinoma was decreased by either RGT or DGT. The blood and urine levels of green tea polyphenols due to tea administration were determined in rats, and the levels were comparable to those in humans after tea ingestion. The above results indicate that both green tea and black tea can inhibit the tumorigenic action of NMBzA during the period of carcinogen treatment and the subsequent molecular events important for esophageal tumorigenesis.