乳酸链球菌素对腹泻小鼠盲肠菌群结构及脂代谢的影响

Effects of Nisin on Caecal Microflora Structure and Lipid Metabolism of Mice with Diarrhea

本试验旨在研究乳酸链球菌素(Nisin)对腹泻小鼠盲肠菌群结构和脂代谢的影响。选择7~9周龄无特定病原体(SPF)级50只小鼠(雌雄各占1/2),随机分成5组,分别为空白对照组、阴性对照组、环丙沙星组、氨苄青霉素组及Nisin组。除空白对照组小鼠腹腔注射等量灭菌生理盐水外,其余各组小鼠连续3 d腹腔注射致病性大肠杆菌(E.coli)O1悬液(2.50×1011CFU/mL)0.2 mL/只构建小鼠腹泻模型。连续注射3 d后,空白对照组和阴性对照组灌胃灭菌生理盐水,其他组灌胃对应物质,每天2次,每次0.3 mL,连续灌胃15 d。第15天灌胃2 h后采样,采用高通量测序技术对小鼠盲肠内容物中细菌结构测序分析,通过酶联免疫吸附测定(ELISA)法对小鼠血清、空肠、回肠和脑组织中金属肽酶含血小板反应蛋白1(ADAMTS1)、总胆固醇(TC)和胰岛素(INS)的含量进行检测。结果显示:与阴性对照组相比,Nisin使小鼠血清、回肠和脑组织中ADAMTS1的含量和回肠中INS的含量显著降低(P<0.05),血清、空肠和脑组织中TC的含量显著增加(P<0.05),并使小鼠各阶段的体重显著增加(P<0.05)。Nisin组小鼠盲肠菌群丰富度最高(ACE指数=2 469.54、Chao1指数=3 340.29)且多样性最高(Shannon指数=7.56),而阴性对照组则最低。Nisin组中疣微菌门(Verrucomicrobia)、蓝细菌门(Cyanobacteria)、拟杆菌门(Bacteroidetes)及厚壁菌门(Firmicutes)为优势菌门。阴性对照组中放线菌门(Actinobacteria)、芽单胞菌门(Gemmatimonadetes)、变形菌门(Proteobacteria)及拟杆菌门为优势菌门。由此得出,Nisin可提高盲肠菌群多样性,降低血清、回肠和脑组织中ADAMTS1的含量和回肠中INS的含量,增加血清、空肠和脑组织中TC的含量,从而影响腹泻小鼠盲肠菌群结构及脂代谢。

The aim of this study was to investigate the effects of Nisin on cecal microflora structure and lipid metabolism of mice with diarrhea.Fifty 7 to 9 weeks old specific pathogen free(SPF)mice(half male and half female)were randomly divided into five groups:blank control group,negative control group,ciprofloxacin group,ampicillin group and Nisin group.The mice in negative control group,ciprofloxacin group,ampicillin group and Nisin group were intraperitoneally injected with pathogenic Escherichia coli suspension(2.50×10 11 CFU/mL)at the dose of 0.2 mL per mouse for successive 3 days to establish the diarrheal model,and the mice in blank control group were intraperitoneally injected with equivalent sterrilled normal saline.After injection 3 days,the mice in blank control group and negative control group were given sterrilled normal saline by gavage,and the mice in other groups were given correspondent substances by gavage for 15 days,the dose of 0.3 mL each time,twice times a day.Samples were collected after 2 h administration on day15,the microflora structure of caecum content was analyzed by high throughput sequencing technology,and the contents of a disintegrin and metalloproteinase with thrombospondin(ADAMTS1),total cholesterol(TC)and insulin(INS)in serum,jejunum,ileum and brain tissue were measured by enzyme-linked immunosorbent assay(ELISA)method.The results showed as follows:compared with the negative control group,Nisin could significantly decrease the ADAMTS1 content in serum,ileum and brain tissue and the INS content in ileum(P<0.05),significantly increase the TC content in serum,jejunum and brain tissue(P<0.05),and significantly increase the body weight of mice in each stage(P<0.05).The caecal microflora richness(ACE index=2 469.54,Chao1 index=3 340.29)and diversity(Shannon index=7.56)of mice in Nisin group were the highest,and those in negative control group were the lowest.Verrucomicrobia,Cyanobacteria,Bacteroidetes and Firmicutes were dominant phylums in Nisin group,and Actinobacteria,Gemmatimonadetes and Proteobacteria were dominant phylums in negative control group.The results indicate that Nisin can enhance the diversity of caecal microflora,decrease the decrease the ADAMTS1 content in serum,ileum and brain tissue and the INS content in ileum,increase the TC content in serum,jejunum and brain tissue,and then affect the cecal microflora structure and lipid metabolism of mice with diarrhea.