Inhibitory effects of orally administered green tea, black tea, and caffeine on skin carcinogenesis in mice previously treated with ultraviolet B light (high-risk mice): relationship to decreased tissue fat.
Inhibitory effects of orally administered green tea, black tea, and caffeine on skin carcinogenesis in mice previously treated with ultraviolet B light (high-risk mice): relationship to decreased tissue fat.
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发表时间：
2001-07
期刊：
影响因子：
11.2
通讯作者：
Y. P. Lu;Y. Lou;Y. Lin;W. Shih;M. Huang;C. S. Yang;A. Conney
中科院分区：
文献类型：
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作者：
Y. P. Lu;Y. Lou;Y. Lin;W. Shih;M. Huang;C. S. Yang;A. Conney
用紫外线B光（UVB; 30 mJ/cm(2)）治疗SKH-1无毛小鼠，每周两次，持续22周，结果在没有额外UVB治疗的情况下，无肿瘤动物在接下来的几个月内发生恶性和非恶性皮肤肿瘤的风险很高（高风险小鼠）。在停止UVB治疗23周后，口服绿茶或红茶（6 mg茶固体/ml）给UVB预处理的高风险SKH-1小鼠，可减少肿瘤数量/只，减少参数脂肪垫的大小，减少远离肿瘤和肿瘤正下方的真皮脂肪层厚度。不含咖啡因的茶对这些参数的影响很小或没有影响，在不含咖啡因的茶中添加咖啡因（相当于普通茶中的量）恢复了它们的抑制作用。单独服用咖啡因也能减少每只小鼠的肿瘤数量，参数脂肪垫的大小，以及远离肿瘤和肿瘤下的真皮脂肪层的厚度。通过对小鼠个体数据进行线性回归和相关分析，我们发现离瘤真皮脂肪层厚度与肿瘤数量/小鼠呈极显著正相关（r = 0.34, P = 0.0001），而平均肿瘤大小/小鼠与离瘤真皮脂肪层厚度相关性较弱（r = 0.16, P = 0.034）。结果表明，p.o.给予的茶或咖啡因可能通过降低真皮中的脂肪水平来减少肿瘤的多样性。另外的分析显示口服含咖啡因的饮料（绿茶，红茶，不含咖啡因的绿茶加咖啡因，不含咖啡因的红茶加咖啡因，或仅含咖啡因）对大肿瘤下真皮脂肪层厚度的减少程度要比小肿瘤下的大得多。这是化学预防剂在抑制癌变和降低组织脂肪水平之间的密切联系的首次证明。
Treatment of SKH-1 hairless mice with ultraviolet B light (UVB; 30 mJ/cm(2)) twice a week for 22 weeks resulted in tumor-free animals with a high risk of developing malignant and nonmalignant skin tumors during the next several months in the absence of additional UVB treatment (high-risk mice). Oral administration of green tea or black tea (6 mg tea solids/ml) to UVB-pretreated high-risk SKH-1 mice for 23 weeks after stopping UVB treatment decreased the number of tumors/mouse, decreased the size of the parametrial fat pads, and decreased the thickness of the dermal fat layer away from tumors and directly under tumors. Administration of the decaffeinated teas had little or no effect on these parameters, and adding caffeine (equivalent to the amount in the regular teas) to the decaffeinated teas restored their inhibitory effects. Administration of caffeine alone also decreased the number of tumors/mouse, the size of the parametrial fat pads, and the thickness of the dermal fat layer away from tumors and under tumors. Using data from individual mice and linear regression and correlation analysis, we found a highly significant positive correlation between the thickness of the dermal fat layer away from tumors and the number of tumors/mouse (r = 0.34; P = 0.0001), but the correlation between average tumor size/mouse and the thickness of the dermal fat layer away from tumors was weak (r = 0.16; P = 0.034). The results suggested that p.o. administered tea or caffeine may have decreased tumor multiplicity in part by decreasing fat levels in the dermis. Additional analysis revealed that oral administration of caffeinated beverages (green tea, black tea, decaffeinated green tea plus caffeine, decaffeinated black tea plus caffeine, or caffeine alone) decreased the thickness of the dermal fat layer under large tumors to a much greater extent than under small tumors. This is the first demonstration of a close association between inhibition of carcinogenesis and the lowering of tissue fat levels by a chemopreventive agent.