Komatsu Shun-ichiro, Isobe Masami, Yanaka Noriyuki, Kato Norihisa
Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima 739-8528, Japan.
Oncol Rep. 2005 Jul;14(1):265-9.
Previously we reported that dietary supplemental vitamin B6 (B6) reduced colon tumorigenesis and cell proliferation in mice receiving azoxymethane (AOM) for 22 weeks. This study was conducted to examine the influence of short-term consumption (5 weeks) of diets containing graded levels of B6 and fat on colonic cell proliferation in mice with or without receiving AOM. In experiment 1, mice were fed the 10% corn oil diet containing 1, 7, 14, 35 or 70 mg pyridoxine HCl/kg, and received weekly injections of AOM for the initial 3 weeks. In experiment 2, mice were fed 5 or 20% corn oil diet containing 1, 7, 14 or 35 mg pyridoxine HCl/kg, and received weekly injections of AOM or saline for the initial 3 weeks. In experiment 1, supplemental B6 caused a dose-dependent reduction of colon aberrant crypt foci and cell proliferation (BrdU-labeling index) among the 1-14 mg pyridoxine HCl/kg. There was no influence of B6 on these parameters among 14-70 mg pyridoxine HCl/kg. Immunohistochemical analysis of apoptosis labeling by TUNEL method indicated no influence of dietary B6 on colon apoptosis. In experiment 2, supplemental B6 significantly reduced colon cell proliferation regardless of AOM injection. This inhibitory effect on cell proliferation was markedly enhanced by a high-fat diet, but slightly affected by AOM treatment. The results suggest that dietary supplemental B6 inhibits colon cell proliferation from the early stage of colon carcinogenesis, and a high-fat diet markedly enhances the inhibitory effect.
此前我们报道，在接受22周偶氮甲烷（AOM）处理的小鼠中，膳食补充维生素B6（B6）可减少结肠肿瘤发生和细胞增殖。本研究旨在考察短期（5周）食用含不同水平B6和脂肪的饮食对接受或未接受AOM处理的小鼠结肠细胞增殖的影响。在实验1中，给小鼠喂食含1、7、14、35或70 mg盐酸吡哆醇/kg的10%玉米油饮食，并在最初3周每周注射AOM。在实验2中，给小鼠喂食含1、7、14或35 mg盐酸吡哆醇/kg的5%或20%玉米油饮食，并在最初3周每周注射AOM或生理盐水。在实验1中，在1 - 14 mg盐酸吡哆醇/kg剂量范围内，补充B6导致结肠异常隐窝灶和细胞增殖（BrdU标记指数）呈剂量依赖性降低。在14 - 70 mg盐酸吡哆醇/kg剂量范围内，B6对这些参数无影响。通过TUNEL法进行的凋亡标记免疫组化分析表明，膳食B6对结肠凋亡无影响。在实验2中，无论是否注射AOM，补充B6均显著降低结肠细胞增殖。高脂饮食显著增强了这种对细胞增殖的抑制作用，但AOM处理对其影响较小。结果表明，膳食补充B（6）从结肠癌发生的早期阶段就抑制结肠细胞增殖，高脂饮食显著增强这种抑制作用。
