Department of Tumor Pathology, Gifu University Graduate School of Medicine, Yanagido, Gifu, Japan.
Oncol Rep. 2010 Jan;23(1):53-9.
Our previous study revealed that fermented brown rice and rice bran (FBRA) suppresses rat colorectal carcinogenesis induced by azoxymethane, the colon-specific carcinogen. In the present study, we examined the suppressive effect of FBRA on colon carcinogenesis in ApcMin/+ mouse, a mouse model for human familial adenomatous polyposis. In contrast to previous findings with the carcinogen-induced model, administration of 5 and 10% FBRA had no effect on the tumor development in the colon of ApcMin/+ mice, suggesting that the modifying effects of FBRA on colorectal carcinogenesis are different depending on rodent models for colorectal carcinogenesis. However, when FBRA is administrated in dextran sodium sulfate (DSS)-exposed ApcMin/+ mouse, a mouse model for the inflammation-related colorectal carcinogenesis, FBRA significantly suppressed the multiplicity of colon tumors in comparison with control diet group. FBRA administration suppressed the cell proliferative index, which is accompanied by the significantly decreased mRNA expressions of Cox2 and iNos in colonic mucosa exposed to DSS (p<0.04 and 0.02, respectively). These findings indicate that FBRA has chemopreventive effects specifically against inflammation-related tumorigenesis in the colon. Our findings also suggest that anti-inflammatory activity is one of the underlying mechanisms by which FBRA suppresses tumorigenesis in the colon.
我们之前的研究表明，发酵糙米和米糠（FBRA）可抑制由偶氮甲烷（一种特定于结肠的致癌剂）诱导的大鼠结直肠癌变。在本研究中，我们研究了 FBRA 对 ApcMin/+ 小鼠（一种人类家族性腺瘤性息肉病的小鼠模型）结直肠癌变的抑制作用。与以前用致癌剂诱导模型的发现相反，5%和 10% FBRA 的给药对 ApcMin/+ 小鼠结肠中的肿瘤发展没有影响，这表明 FBRA 对结直肠癌变的修饰作用因结直肠癌变的啮齿动物模型而异。然而，当 FBRA 在葡聚糖硫酸钠（DSS）暴露的 ApcMin/+ 小鼠（一种与炎症相关的结直肠癌变的小鼠模型）中给药时，与对照饮食组相比，FBRA 显著抑制了结肠肿瘤的多发性。FBRA 给药抑制了细胞增殖指数，这伴随着 DSS 暴露的结肠黏膜中 Cox2 和 iNos 的 mRNA 表达显著降低（分别为 p<0.04 和 0.02）。这些发现表明，FBRA 对结肠中与炎症相关的肿瘤发生具有化学预防作用。我们的研究结果还表明，抗炎活性是 FBRA 抑制结肠肿瘤发生的潜在机制之一。
