基于16S rDNA测序的自身免疫性甲状腺疾病患者肠道菌群研究

探讨Graves病患者、桥本甲状腺炎患者及健康人的肠道菌群结构、多样性和丰度差异。

选取2020年8月至2020年12月于湖北省中医院甲状腺疾病诊疗中心就诊的新诊断且未经治疗的Graves病患者（GD组）、桥本甲状腺炎患者（HT组）各15例以及15例年龄、性别相匹配的健康受试者（健康对照组）。采集参与者粪便样本，采用16S rDNA高通量测序法分析肠道菌群，比较各组对象肠道菌群物种组成及丰度差异。

与健康对照组相比，GD组患者肠道菌群Sobs指数、Ace指数、Chao指数偏低，Coverage指数偏高（均P＜0.05）。GD组与HT组以及HT组与健康对照组比较，其肠道菌群Sobs指数、Ace指数、Chao指数、Coverage指数差异均无统计学意义（均P＞0.05）。3组对象肠道优势菌门为拟杆菌门、厚壁菌门、变形菌门、梭杆菌门。瘤胃球菌属、罗斯伯里菌属、罗姆布茨菌属、链球菌属等在3组对象中差异均有统计学意义（均P＜0.05），其中GD组患者肠道乳杆菌目、链球菌属、链球菌科的相对丰度较高；HT组患者肠道瘤胃球菌属、消化链球菌科、消化链球菌—蒂氏菌目、罗姆布茨菌、梭菌科、严格厌氧梭状芽胞杆菌1、梭菌目的相对丰度较高；而罗斯伯里菌属、光冈菌属在健康对照组中丰度较高。GD组患者肠道中严格厌氧梭状芽胞杆菌1、Odoribacter、Phocea丰度低于HT组，而Streptococcus的丰度高于HT组（均P＜0.05）。

Graves病患者、桥本甲状腺炎患者的肠道菌群与健康人群有显著差异，促进脂肪累积与能量吸收的菌群在Graves病患者中降低，而条件致病菌在自身免疫性甲状腺疾病患者中丰度增加，这些菌种变化可能通过破坏肠道稳态，干预免疫调节，促进炎症反应介导自身免疫性甲状腺疾病的发病。严格厌氧梭状芽胞杆菌1、Odoribacter、Phocea、链球菌属可能是Graves病和桥本甲状腺炎的关键差异菌属，但还需要进一步的研究以明确这些菌株介导疾病的机制。

Intestinal flora in patients with autoimmune thyroid disease based on 16S rDNA sequencing

ObjectiveTo explore the differences in the structure, diversity and abundance of intestinal flora among patients with Graves' disease, Hashimoto's thyroiditis and healthy individuals. MethodsFifteen newly diagnosed and untreated patients with Graves' disease (GD group), 15 ones with Hashimoto's thyroiditis (HT group) and 15 age- and sex-matched healthy subjects (control group) attending the Thyroid Disease Clinic from August 2020 to December 2020 were selected. The stool samples of participants were collected for microbiota analysis using 16S rDNA sequencing to compare the differences in species composition and abundance of intestinal flora among the groups. ResultsCompared with the control group, the indexes of Sobs, Ace and Chao in GD group decreased, and the Coverage index increased (all P＜0.05). There were no significant differences in the indexes of Sobs, Ace, Chao and Coverage between GD group and HT group and between HT group and control group (all P＞0.05). The dominant phyla in the three groups were Bacteroidota, Firmicutes, Proteobacteria and Fusobacteriota. Ruminococcus, Roseburia, Romboutsia and Streptococcus showed statistically significant differences among the three groups (all P＜0.05). The GD group had a higher relative abundances of Lactobacillales, Streptococcus and Streptococcaceae, the HT group had higher relative abundances of Ruminococcus, Peptostreptococcaceae, Peptostreptococcales-Tissierellales, Romboutsia, Clostridiaceae, Clostridium_sensu_stricto_1 and Clostridiales, while Roseburia and Mitsuokella were enriched in the control group. The abundances of Clostridium_sensu_stricto_1, Odoribacter and Phocea in GD group were lower, while that of Streptococcus was higher than in HT group respectively (all P＜0.05). ConclusionThe intestinal flora of patients with Graves' disease and Hashimoto's thyroiditis are significantly different from that of the healthy population, with the flora promoting fat accumulation and energy absorption being reduced in patients with Graves' disease and the abundance of conditionally pathogenic bacteria being increased in patients with autoimmune thyroid disease. These changes may mediate the development of autoimmune thyroid disease by disrupting intestinal homeostasis, interfering with immune regulation and promoting an inflammatory response. This study is the first to identify Clostridium_sensu_stricto_1, Odoribacter, Phocea and Streptococcus as the key differentiator of Graves' disease and Hashimoto's thyroiditis, but further research is needed to clarify the mechanisms by which these strains mediate the disease.