Inhibitory effect of chloroform-resistant bacteria on polyposis in the small intestine of gnotobiote BALB/c mice

研究了BALB/c无菌小鼠小肠自发性息肉病的发生。以无菌（GF）小鼠为基础，给予不同的肠道菌群培养GB小鼠。CRB组小鼠的息肉发病率和每只小鼠的息肉数量低于GF组，而GB组小鼠的息肉发生率高于GF组小鼠。这表明在GB BALB/c小鼠中，CRB的存在抑制了息肉病的发生。研究了化学致癌物对无菌BALB/c小鼠小肠自发性息肉病的影响。8 ~ 29周龄（MNNG- y组）和30 ~ 45周龄（MNNG- a组）小鼠随机饮水中添加n -甲基-n′-硝基-n -亚硝基胍（MNNG） 100杯/ml。分别从8周龄（DMH- y组）和30周龄（DMH- a组）开始，每周腹腔注射1,2-二甲基肼（DMH， 20 mg/kg体重），连续5周。12月龄时，处死并仔细解剖小肠息肉数量。接受致癌物治疗组的息肉病发生率明显高于未接受致癌物治疗的对照组。经组织病理学检查，经不同致癌物治疗后，息肉未明显转为恶性。本研究提示，致癌物能增加息肉的数量，而在无菌BALB/c小鼠小肠中未发现恶性息肉的发生。本文研究了BALB/c细菌（GB）小鼠小肠自发性息肉病与氯仿耐药菌（CRB）、梭形菌（FB）和节段丝状菌（SFB）的相关性。CRB和FB小鼠的息肉发病率和每只小鼠息肉数显著低于GF小鼠（p<<0.05）， SFB小鼠与GF小鼠无显著差异。这表明在GB BALB/c小鼠中，CRB或FB的存在抑制了息肉病的发生。CRB和FB小鼠的蛋白质含量显著低于CF小鼠（p<<0.05）， SEB小鼠的蛋白质含量与GF小鼠无显著差异。这表明在GB BALB/c小鼠中，CRB或FB的存在抑制了息肉病的发生。少

The spontaneous polyposis in the small intestine of BALB/c gnotobiotic (GB) mice was studied. GB mice were derived from the germ-free (GF) mice by administering various strains of intestinal bacteria. Incidence of polyposis and the number of polyps per mouse were lower for CRB mice, and higher for groups of GB mice than for GF mice. This suggests that the polyposis was inhibited by the presence of the CRB in GB BALB/c mice.The influences of chemical carcinogens on spontaneous polyposis in the small intestine of germfree BALB/c mice was studied. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in drinking water (100 mug/ml) was given to mice from 8 to 29 weeks of age (MNNG-Y group) and from 30 to 45 weeks of age (MNNG-A group) ad lib., and 1,2-Dimethylhydrazine dihydrochloride (DMH ; 20 mg/kg body weight) were administered intraperitonealy injection at weekly interval for 5 weeks from 8 weeks old (DMH-Y group) and 30 weeks old (DMH-A group), respectively, When the animals were 12 months old, … More they were killed and autopsied carefully for the number of polyps in the small intestine. The incidence of polyposis was significantly higher in all groups of treated with carcinogens than in non-treated control group. In histopathological examination, the polyp was not distinctly led to the malignancy by treating with different carcinogens. The present study suggested that number of polyps was enhanced by treating with carcinogens, while there was no evidence for the development of malignant polyps in the small intestine of germ free BALB/c mice.The spontaneous polyposis in the small intestine of BALB/c gnotobiotic (GB) mice associated with chloroform resistant bacteria (CRB), fusiform bacteria (FB) and segmented filamentous bacteria (SFB), respectively, was studied. Incidence of polyposis and the number of polyps per mouse were significantly lower for CRB and FB mice than for GF mice (p<<0.05), and those for SFB mice was not different from those of GF mice. This suggests that the polyposis was inhibited by the presence of the CRB or FB in GB BALB/c mice. significantly lower for CRB and FB mice than for CF mice (p<<0.05), and those for SEB mice was not different from those of GF mice. This suggests that the polyposis was inhibited by the presence of the CRB or FB in GB BALB/c mice. Less