Abstract: Objective To investigate the changes in gut microbiota in preschool obese children and their association with body mass index (BMI),and help further study on prevention and therapy of obesity. Methods Twenty-nine obese preschool children aged 3~6 years old and 34 normal-weight children with similar age and sex ratio from 2 kindergartens in Beijing in 2014,were included in the study.Microbial DNA was extracted from the morning fecal samples and the V4-V5 region of the bacteria 16S ribosomal RNA gene were amplified by PCR.Then the Illumina MiSeq sequencing was used to examine the gut microbiota. Results Compared to the normal-weight children (6.42%±1.10%),the level of Proteobacteria (10.75%±2.00%) was significantly increased in obese children (P<0.05); whereas no changes were found in levels of Firmicutes (2.90%±10.79% vs.62.41%±11.59%),Bacteroidetes (19.19%±3.29% vs.16.36%±3.04%),Actinobacteria (9.69%±1.66% vs.9.28%±1.72%),Lactobacillus (0.08%±0.01% vs.0.07%±0.01%),Bacteroides (2.73%±0.47% vs.3.81%±0.71%),Bifidobacterium (8.09%±1.39% vs.8.25%±1.53%) and Escherichia-Shigella (3.94%±0.67% vs.5.78%±1.07%) between the normal-weight and obese groups (P>0.05).Correlative analysis showed that the level of Proteobacteria was positively associated with BMI,and other phyla and genera had no association with BMI (P>0.05). Conclusion The increased Proteobacteria level may play an important role in obesity of preschool children.

Key words: obesity, gut microbiota, preschool children

摘要： 目的 探讨肥胖儿童肠道菌群的改变及其与儿童体质指数(body mass index,BMI)之间的关系,为进一步研究儿童肥胖的预防及治疗奠定基础。方法 于2014年在北京市2所幼儿园选取29例3～6岁的单纯性肥胖儿童及34例性别、年龄相近的正常儿童,采集清晨粪便并从中提取菌群DNA,然后针对16S rRNA的V4-V5区进行PCR扩增,采用二代测序Illumina MiSeq方法在门和属的水平上检测肠道菌群的变化;进而分析其与儿童BMI之间的相关关系。结果 肥胖儿童粪便中变形菌门水平(10.75%±2.00%)明显高于正常儿童(6.42%±1.10%)(P<0.05);厚壁菌门(62.41%±11.59%)、拟杆菌门(16.36 %±3.04%)、放线菌门(9.28%±1.72%)及乳杆菌属(0.07%±0.01%)、拟杆菌属(3.81%±0.71%)、双歧杆菌属(8.25%±1.53%)及大肠志贺菌属(5.78%±1.07%)与正常儿童之间(62.90 %±10.79%、19.19%±3.29%、9.69%±1.66%、0.08%±0.01%、2.73%±0.47%、8.09%±1.39%、3.94%±0.67%)差异均无统计学意义(P>0.05)。相关分析显示,变形菌门水平与儿童BMI水平呈显著正相关关系(r=0.009 5,P<0.05),而其他菌门和菌属与BMI之间无相关性(P>0.05)。结论 在所研究的人群范围内,肠道变形菌门比例增加可能在学龄前儿童肥胖发生中起着重要的作用。

关键词: 肥胖, 肠道菌群, 学龄前儿童