摘要：目的：维生素B12（Vitamin B12,VitB12）为B族维生素之一，是一类含钴的复杂有机化合物。肠炎(Inflammatory bowel disease，简称IBD）容易引起贫血，通过补充维生素B12可以缓解肠炎的症状。但是有研究表明，某些VitB12的摄入可能加重肠炎。因此，本研究将对各种VitB12衍生物对硫酸化右旋糖苷钠（dextran sulfate sodium，简称DSS）所致小鼠IBD的作用及其机制进行研究。方法和结果： 60只小鼠（C571/B6小鼠，雄性，8-10周）随机的分为10组：对照组、IBD组、IBD+VitB12衍生物氰钴胺组（低浓度、中浓度、高浓度）、IBD+VitB12衍生物甲钴胺组（低浓度、中浓度、高浓度）、氰钴胺高浓度组、甲钴胺高浓度组。除对照组外，其余9组先喂食5%的DSS溶液2天诱导IBD，之后IBD组继续喂食5%DSS溶液，IBD+氰钴胺组喂食5%DSS和对应浓度的氰钴胺浓度，IBD+甲钴胺组喂食5%DSS和对应浓度的甲钴胺溶液，氰钴胺高浓度组喂食高浓度的氰钴胺溶液，甲钴胺高浓度组喂食高浓度的甲钴胺溶液。接着我们对IBD小鼠进行了DAI评分、肠炎指数评价，结果是第8天IBD+甲钴胺组的DAI评分低于IBD组，而IBD+氰钴胺组的DAI评分与IBD组接近；IBD+甲钴胺组的大肠炎症程度低于IBD组和IBD+氰钴胺组。最后我们检测了小鼠粪便中的有机酸种属和含量，得到粪便中含有6种有机酸，其中5种与IBD的发生有关。结论：VitB12衍生物甲钴胺对DSS所致IBD有很好的缓解作用，而VitB12衍生物氰钴胺会加重DSS所致的IBD，这有可能是通过VitB12的衍生物引起了肠道中菌群的变化，而甲钴胺能抑制有害菌群的生成、保护有益菌群的生长，氰钴胺则会增加有害菌群的生成。90313

Abstract：Aim:Vitamin B12 is one of the B vitamins and a kind of complex organic compounds containting cobalt。IBD is easy to canuse anemia。Administracting Vitamin B12 could relief symptoms of IBD。However,there were some studies that intaking some Vitamin B12 derivatives exacerbated IBD。Therefor,this study aimed to investigate the effect and underlying mechenanism of Vitamin B12 derivatives in dextran sulfate sodium(DSS)-induced induced Inflammatory Bowel Disease(IBD)。

Methods and results:60 C57BL/6J  mice ( all male,8-10 weeks) was pided into groups randomly:conteol group(CN)、IBD group、IBD + Cyanocobalamin (low concentration、medium concentration、high concentration) group、IBD + Methylcobalamin (low concentration、medium concentration、high concentration) group、Cyanocobalamin  high concentration group、Methylcobalamin high concentration group。Except the CN,other groups were administrated 5% DSS solution two days for inducing IBD firstly。Then IBD group continued administrating 5% DSS solution and IBD+VB12 group was administrated corresponding derivative and homologous concentration and 5%DSS solution。The mice of Cyanocobalamin  high concentration group fed high concentration Cyanocobalamin solution and the mice of Methylcobalamin  high concentration group fed high concentration Methylcobalaminsolution。Then we evaluated the DAI score of the mice with IBD and evaluated the index of enteritis。It found that the DAI score of IBD + Methylcobalamin group was lower than that of IBD group on day 8, while the DAI score of  IBD + Cyanocobalamin group was close to that of IBD group。 The degree of colitis in the IBD + Methylcobalamin group was lower than that in the IBD group and the IBD + Cyanocobalamin group。 Finally, we tested the genotypes and contents of the organic acids in the feces of the mice,and contained six kinds of organic acids in the feces。 Five of them were related to the occurrence of IBD。

Conclusion: Vitamin B12 derivatives -Methylcobalamin  has a good effect on  curing DSS-induced IBD, while Vitamin B12 derivatives Cyanocobalamin can exacerbate DSS-induced IBD。It may be coused by the derivatives of Vitamin B12caused changing of gut microflora,and Methylcobalamin can inhibit the formation of harmful bacteria,the protection of benefical bacteria growth。Cyanocobalamin may be increase the generation of harmful bacteria。