云芝糖肽对氧化偶氮甲烷-葡聚糖硫酸钠诱导小鼠结直肠癌模型中相关肠道菌的影响及潜在意义

Effects of polysaccharopeptide of Trametes versicolor on cancer-associated pathogenic enterobacteria in AOM/DSS-induced colorectal cancer mouse model

旨在探究云芝糖肽(polysaccharopeptide, PSP)对炎症相关结直肠癌(colorectal cancer, CRC)模型小鼠中肠道潜在致病菌和益生菌的影响。将雄性C57BL/6小鼠随机分为对照组、模型组和PSP组,每组10只。模型组和PSP组以氧化偶氮甲烷(azoxymethane,AOM)/葡聚糖硫酸钠(dextran sodium sulfate,DSS)造模。PSP组在造模基础上每日灌胃PSP 650 mg/kg,持续13周。小鼠炎症状态以疾病活动指数(disease activity index, DAI)进行评估。采用实时荧光定量聚合酶链反应技术测定各组小鼠新鲜粪便中厌氧消化链球菌(Peptostreptococcus anaerobius,P.anaerobius)、嗜黏蛋白阿克曼菌(Akkermansia muciniphila,A.muciniphila)、脆弱拟杆菌(Bacteroides fragilis,B.fragilis)、共生梭菌(Clostridium symbiosum,C.symbiosum)及乳酸杆菌(Lactobacillus spp.)的相对丰度。结果显示,PSP可降低造模所导致的小鼠DAI值升高,且在前两轮DSS处理时与模型组比较有显著性差异(P<0.05、P<0.01)。PSP下调潜在致病菌P.anaerobius、A.muciniphila、B.fragilis以及C.symbiosum的相对丰度,且中期时P.anaerobius、A.muciniphila、B.fragilis的丰度均显著低于初始水平(P<0.05、P<0.01、P<0.05)。表明PSP可缓解致炎剂诱导的小鼠结肠炎症,并降低部分肠道致病菌的相对丰度,提示PSP对炎症相关CRC可能具有潜在的预防作用。

To investigate the effects of polysaccharopeptide(PSP) of Trametes versicolor on colorectal cancer-associated pathogenic enterobacteria(CAPEB), male mice were randomly divided into three groups: wild type group, Model group and PSP group. The mice in Model and PSP group were intraperitoneally injected with azoxymethane(AOM) and administrated with three cycles of dextran sodium sulfate(DSS) in drinking water to induce colorectal cancer. Mice in the PSP group were administrated daily with PSP(650 mg/kg) by gavage for 13 weeks. Diseases active indexes(DAI) were scored during the three DSS cycles, and the relative abundances of bacteria in stool samples were determined by quantitative real-time polymerase chain reaction. The results showed that the DAI of the PSP group was significantly decreased in the first two rounds of DSS treatment(P<0.05, P<0.01) compared to the model group. The relative abundances of each potential CAPEB of the PSP group, in terms of P. anaerobius, A. muciniphila, B. fragilis and C. symbiosum, were all lower than those of the model group, and the abundance of the first three bacteria mentioned above was significantly decreased in the mid-term of the experiment(P<0.05, P<0.01, P<0.05). These results indicated that PSP could alleviate DSS-induced inflammation and down-regulate abundance of colorectal cancer-associated pathogenic enterobacteria in mice, suggesting that PSP may have a preventive effect on inflammation-associated colorectal cancer.