Objectives: To study the effect of gut microbiota on hematopoiesis in a neonatal rat model of necrotizing enterocolitis (NEC).
Methods: Neonatal Sprague-Dawley rats were randomly divided into a control group and a model group (NEC group), with 6 rats in each group. Formula milk combined with hypoxia and cold stimulation was used to establish a neonatal rat model of NEC. Hematoxylin and eosin staining was used to observe the pathological changes of intestinal tissue and hematopoiesis-related organs. Routine blood tests were conducted for each group. Immunohistochemistry was used to observe the changes in specific cells in hematopoiesis-related organs. Flow cytometry was used to measure the changes in specific cells in bone marrow. 16S rDNA sequencing was used to observe the composition and abundance of gut microbiota.
Results: Compared with the control group, the NEC group had intestinal congestion and necrosis, damage, atrophy, and shedding of intestinal villi, and a significant increase in NEC histological score. Compared with the control group, the NEC group had significantly lower numbers of peripheral blood leukocytes and lymphocytes (P<0.05), nucleated cells in the spleen, thymus, and bone marrow, and small cell aggregates with basophilic nuclei in the liver (P<0.05). The NEC group had significant reductions in CD71+ erythroid progenitor cells in the liver, CD45+ lymphocytes in the spleen and bone marrow, CD3+ T lymphocytes in thymus, and the proportion of CD45+CD3-CD43+SSChi neutrophils in bone marrow (P<0.05). There was a significant difference in the composition of gut microbiota between the NEC and control groups, and the NEC group had a significant reduction in the abundance of Ligilactobacillus and a significant increase in the abundance of Escherichia-Shigella (P<0.05), which replaced Ligilactobacillus and became the dominant flora.
Conclusions: Multi-lineage hematopoietic disorder may be observed in a neonatal rat model of NEC, which may be associated with gut microbiota dysbiosis and abnormal multiplication of the pathogenic bacteria Escherichia-Shigella.
目的: 探讨肠道菌群对坏死性小肠结肠炎（necrotizing enterocolitis，NEC）新生大鼠模型造血系统的影响。方法: Sprague-Dawley新生大鼠随机分为对照组和模型组（NEC组），每组6只。采用配方奶结合缺氧和冷刺激构建NEC新生大鼠模型。苏木精-伊红染色观察肠组织及造血相关器官病理变化；检测各组血常规；免疫组化法检测造血相关器官中特定细胞的改变；流式细胞术检测骨髓中特定细胞的变化；采用16S rDNA测序技术检测分析各组肠道菌群的组成及丰度。结果: 与对照组比较，NEC组肠组织充血坏死，肠绒毛破损、萎缩脱落，NEC病理评分显著增加；NEC组外周血白细胞及淋巴细胞计数显著低于对照组（P<0.05）；NEC组脾脏、胸腺、骨髓的有核细胞及肝脏的嗜碱性细胞核的小细胞聚集体数量均明显少于对照组；NEC组肝脏中CD71+红系祖细胞显著减少，脾脏、骨髓中的CD45+白细胞及胸腺中的CD3+ T淋巴细胞显著降低，骨髓中CD45+CD3-CD43+SSChi的中性粒细胞比例明显下降（P<0.05）；NEC组肠道菌群组成与对照组比较差异明显，NEC组利乳杆菌属的相对丰度降低，而埃希菌-志贺菌属的相对丰度显著升高（P<0.05），取代利乳杆菌属成为优势菌属。结论: NEC新生大鼠模型存在多谱系造血异常，可能与肠道微生物稳态失衡及致病菌属埃希菌-志贺菌属的异常扩增有关。.
Keywords: Gut microbiota; Hematopoietic disorder; Necrotizing enterocolitis; Neonatal rat.