Abstract: Objective　To investigate the characteristics of gut microbiota in retired aged C57BL/6 mice. Methods　Rectal content samples were collected from female C57BL/6 mice at 8 weeks of age (control group,n=10) and retired mice at 72 weeks of age (aged group,n=10). The V3-V4 hypervariable region of the 16S rRNA gene was amplified using universal primers and sequenced via high-throughput sequencing technology. Microbial community composition and diversity indices were analyzed using QIIME software, while linear discriminant analysis effect size (LEfSe) was employed to identify statistically significant microbial biomarkers between the two groups.Results　A total of 1 618 804 high quality 16S rRNA sequences were obtained from the gut microbiota samples of 20 C57BL/6 mice. At the phylum level, Bacteroidetes and Firmicutes were the dominant taxa with relatively high abundance in both  groups. Alpha diversity analysis revealed no significant differences between the two groups in any of the five indices measured: Observed features, Chao1, Shannon, Simpson, and Good's coverage. However, beta diversity analysis indicated a statistically significant separation in microbial community structure between the aged group and the control group (P<0.05). LEfSe analysis revealed that bacteria from the class Coriobacteriia, order Coriobacteriales, family Eggerthellaceae, and genus Enterorhabdus were identified as significant biomarkers in the gut microbiota of the aged group mice. In contrast, bacteria belonging to the order of Clostridia-UCG-014, family Rikenellaceae, and genus Alistipes were significantly enriched in the gut microbiota of the control group mice.Conclusion　This study characterized the composition and abundance of the gut microbiota in rectal contents of retired aged C57BL/6 mice using 16S rRNA high-throughput sequencing. These findings provide fundamental data for understanding the biological characteristics of retired aged C57BL/6 mice and offer valuable reference information for the selection of appropriate animal models in aging-related research.

Key words: aging, C57BL/6 mice, gut microbiota, 16S rRNA high-throughput sequencing

摘要： 目的　研究退役老龄C57BL/6小鼠的肠道菌群特征。方法　分别收集雌性8周龄(对照组,10只)和退役72 周龄(老年组,10只)C57BL/6小鼠的直肠内容物样品,采用16S rRNA通用引物扩增V3-V4区并进行高通量测序, 使用QIIME软件对不同组样品中菌群组成和多样性指标进行分析,使用线性判别分析效应大小(LEfSe)软件比较 各组样品中具有统计学差异的菌群标志物。结果　从20只C57BL/6小鼠的肠道菌群样本中共获得16S rRNA有 效序列1 618 804条。在门水平上,拟杆菌门和厚壁菌门在两组样品中都是相对丰度较高的优势菌。α多态性分析 结果显示,Observed features、Chao1、Shannon、Simpson、Good′s coverage等5项指标在两组样品中均无显著差异(P> 0.05);β多态性分析结果显示,老龄组小鼠与对照组小鼠肠道内容物样品差异有统计学意义(P<0.05);LEfSe分析 结果表明,在老龄组小鼠的肠道菌群中,红蝽菌纲(Coriobacteriia),红蝽菌目(Coriobacteriales),埃格特菌科 (Eggerthellaceae)和肠杆菌属(Enterorhabdus)的细菌被鉴定为具有显著性差异的生物标志物。Clostridia-UCG-014所 属的目,理研菌科(Rikenellaceae)和另枝菌属(Alistipes)的细菌则在对照组小鼠的肠道菌群内显著富集。结论　本研 究利用16S rRNA 高通量测序分析了退役老龄C57BL/6小鼠直肠内容物肠道菌群的组成、丰度等基本特点,为深入 了解退役老龄C57BL/6小鼠的生物学特性,以及开展衰老相关研究中动物模型的选用提供了基础数据。

关键词: 衰老, C57BL/6小鼠, 肠道菌群, 16S rRNA 高通量测序