Characteristics of gut microbiota in representative mice strains: Implications for biological research

Abstract

Background: Experimental animals are used to study physiological phenomena, pathological mechanisms, and disease prevention. The gut microbiome is known as a potential confounding factor for inconsistent data from preclinical studies. Although many gut microbiome studies have been conducted in recent decades, few have focused on gut microbiota fluctuation among representative mouse strains.Methods: A range of frequently used mouse strains were selected from 34 isolation packages representing disease-related animal (DRA), immunity defect animal (IDA), or gene-editing animal (GEA) from the BALB/c and C57BL/6J backgrounds together with normal mice, and their microbial genomic DNA were isolated from mouse feces to sequence for the exploration of gut microbiota.Results: Mouse background strain, classification, introduced source, introduced year, and reproduction type significantly affected the gut microbiota structure (p < 0.001 for all parameters), with background strain contributing the greatest influence (R 2 = 0.237). In normal groups, distinct gut microbiota types existed in different mouse strains. Sixty-four core operational taxonomic units were obtained from normal mice, and 12 belonged to Lactobacillus. Interestingly, the gut microbiota in C57BL/6J was more stable than that in BALB/c mice. Furthermore, the gut microbiota in the IDA, GEA, and DRA groups significantly differed from that in normal groups (p < 0.001 for all). Compared with the normal group, there was a significantly higher Chao1 and Shannon index (p < 0.001 for all) in the IDA, GEA, and DRA groups. Markedly changed classes occurred with Firmicutes and Bacteroidetes. The abundances of Helicobacter, Blautia, Enterobacter, Bacillus, Clostridioides, Paenibacillus, and Clostridiales all significantly decreased in the IDA, GEA, and DRA groups, whereas those of Saccharimonas, Rikenella, and Odoribacter all significantly increased.

The gut microbiota is important for the maintenance of blood–cerebrospinal fluid barrier integrity

“…Our results in the blood–CSF barrier complement previous studies that found germ‐free mice have lower tight junction protein expression in the BBB (Braniste et al, 2014), further implicating the gut microbiota in the regulation and maintenance of brain barrier integrity. Although we did not measure the gut microbiota composition in this study, the conventional mice were all raised under the same variables known to influence the gut microbiota composition (i.e., diet and light cycles) (Guo et al, 2022). Additionally, even if we were to have seen variation in microbiota composition among the conventional mice, we did not see different clusters in ZO‐1 network quantification.…”

Identifying genetic susceptibility to Aspergillus fumigatus infection using collaborative cross mice and RNA‐Seq approach

“…Some strains show resistance to the infection, while others show sensitivity to the infection, presumably due to the genetic diversity of the CC founders (mouse being the most commonly used animal model) 45 . This demonstrates the ability of the CC resource to provide high‐resolution mapping of QTL affecting a wide variety of traits, including susceptibility to a spectrum of infectious diseases 36,46,47 …”

Notch dimerization provides robustness against environmental insults and is required for vascular integrity

“…Both diets used are considered standard rodent chow, but the extruded diet lacks fish meal and soy products (S1 Table ), which can be a source of the pro-inflammatory molecules nitrosamines and isoflavones [27][28][29]. Genetic background and sex influences barrier formation, DSS sensitivity, microbiome composition and cytokine expression [30][31][32][33]; therefore, to reduce their confounding effects, we used isogenic C57BL/6 male mice for all DSS treatment analyses unless otherwise stated. Mice were housed under each respective housing condition for a minimum of 4 weeks before treatment with 1% or 2.5% DSS.…”