小檗碱通过调节肠道微生物群抑制肠道促炎基因和致癌因子抑制肠道癌变。

BACKGROUND: The role of Berberine (BBR) in colorectal cancer (CRC) and gut microbiota has begun to appreciate. However, there was no direct evidence confirm that the gut microbiota regulated by BBR could inhibit CRC. This report investigated the effect of stool from BBR treated subjects and its effect on CRC. METHODS: A mouse model for CRC was developed using azoxymethane (AOM) and dextran sulfate sodium (DSS). Intestinal tissue from affected mice were used to determine the efficacy of BBR against CRC. Stool samples were collected for the 16s rRNA gene sequencing and fecal microbiota transplantation (FMT). Finally, the mechanism of gut microbiota from BBR treated mice on CRC was explored using immunohistochemistry, RNA-Sequencing, quantitative RT-PCR, and western blot analyses. RESULTS: BBR significantly reduced intestinal tumor development. The richness of gut microbiota were notably decreased by BBR. Specifically, the relative abundance of beneficial bacteria (Roseburia, Eubacterium, Ruminococcaceae, and Firmicutes_unclassified) was increased while the level of bacteria (Odoribacter, Muribaculum, Mucispirillum, and Parasutterella) was decreased by BBR treatment. FMT experiment determined that the mice fed with stool from BBR treated AOM/DSS mice demonstrated a relatively lower abundance of macroscopic polyps and a significantly lower expression of β-catenin, and PCNA in intestinal tissue than mice fed with stool from AOM/DSS mice. Mechanistically, intestinal tissue obtained from mice fed with stool from BBR treated AOM/DSS mice demonstrated a decreased expression of inflammatory cytokines including interleukin 1β (IL-1β), tumor necrosis factor-α (TNF-α), C-C motif chemokine 1 (Ccl1), Ccl6, and C-X-C motif ligand (Cxcl9). In addition, the NF-κB expression was greatly suppressed in mice fed with stool from BBR treated AOM/DSS mice. Real-time PCR arrays revealed a down-regulation of genes involved in cell proliferation, angiogenesis, invasiveness, and metastasis in mice fed with stool from BBR treated AOM/DSS mice. CONCLUSIONS: Stool obtained from BBR treated AOM/DSS mice was able to increase colon length while simultaneously decreasing the density of macroscopic polyps, cell proliferation, inflammatory modulators and the expression of NF-κB. Therefore, it was concluded that suppression of pro-inflammatory genes and carcinogens factors by modulating gut microbiota was an important pathway for BBR to inhibit tumor growth in conventional mice.

背景：小檗碱（BBR）在结直肠癌（CRC）和肠道微生物群中的作用开始受到关注。然而，没有直接证据证实 BBR 调节的肠道微生物群可以抑制 CRC。本报告研究了 BBR 处理后的粪便对 CRC 的影响及其作用。

方法：使用氧化偶氮甲烷（AOM）和葡聚糖硫酸钠（DSS）建立 CRC 小鼠模型。使用受影响小鼠的肠道组织确定 BBR 对 CRC 的疗效。收集粪便样本进行 16s rRNA 基因测序和粪便微生物群移植（FMT）。最后，使用免疫组织化学、RNA 测序、定量 RT-PCR 和 Western blot 分析探索 BBR 处理小鼠肠道微生物群对 CRC 的作用机制。

结果：BBR 可显著降低肠道肿瘤的发生。BBR 明显降低了肠道微生物群的丰富度。具体而言，有益细菌（Roseburia、Eubacterium、Ruminococcaceae 和 Firmicutes_unclassified）的相对丰度增加，而细菌（Odoribacter、Muribaculum、Mucispirillum 和 Parasutterella）的水平降低。FMT 实验确定，喂食 BBR 处理的 AOM/DSS 小鼠粪便的小鼠表现出较少的宏观息肉和肠道组织中β-连环蛋白和 PCNA 的表达显著降低，而喂食 AOM/DSS 小鼠粪便的小鼠则表现出较多的宏观息肉和肠道组织中β-连环蛋白和 PCNA 的表达显著降低。机制上，喂食 BBR 处理的 AOM/DSS 小鼠粪便的小鼠肠道组织中促炎细胞因子的表达降低，包括白细胞介素 1β（IL-1β）、肿瘤坏死因子-α（TNF-α）、C-C 基序趋化因子 1（Ccl1）、Ccl6 和 C-X-C 基序配体（Cxcl9）。此外，喂食 BBR 处理的 AOM/DSS 小鼠粪便的小鼠中 NF-κB 的表达受到极大抑制。实时 PCR 阵列显示，喂食 BBR 处理的 AOM/DSS 小鼠粪便的小鼠中与细胞增殖、血管生成、侵袭和转移相关的基因表达下调。

结论：从 BBR 处理的 AOM/DSS 小鼠获得的粪便能够增加结肠长度，同时减少宏观息肉的密度、细胞增殖、炎症调节剂和 NF-κB 的表达。因此，结论是通过调节肠道微生物群抑制促炎基因和致癌因素是 BBR 抑制常规小鼠肿瘤生长的重要途径。