π‘ Germ-free (GF) rodents have become crucial for unraveling the impact of intestinal microbes on host physiology. The most prominent GF phenotype is an enlarged cecum, attributed to the absence of microbial colonization. However, the role of host genetic background in cecal enlargement remains unknown.
This study investigates the influence of mouse genetic background on cecal size in five commonly used GF strains: B6J, B6N, NMRI, BALBc, and C3H. The results reveal significant variations in cecal weight, with B6 background mice exhibiting the largest ceca (up to 20% of total body weight) and C3H mice the smallest (up to 5%).
The study explores the underlying mechanisms, linking genetic factors to water transport, mucin production, and metabolic profiles.
π Key Scientific Findings:
π Genetic Background and Cecal Enlargement: Host genetic background plays a pivotal role in determining the extent of cecal enlargement in GF rodents. Significant variations exist among five GF strains, with B6 background mice showing the largest ceca and C3H mice the smallest.
π Water Transport and Cecal Size: Reduced cecal size in GF C3H mice correlates with decreased water content and increased expression of water transporters (Slc2a5, Slc5a1, and AQP4). Water absorption is suggested to be enhanced in GF C3H mice, influencing cecal size.
π Metabolic Profiles and Cecal Enlargement: Distinct metabolic profiles contribute to cecal enlargement differences. GF B6J mice exhibit altered amino acid and bile acid metabolism, along with increased levels of humectant L-pyroglumatic acid (PCA) and taurine-conjugated primary bile acids.
π Mucin Production and Cecal Size: GF B6J mice display increased production of acidic mucins in the cecal mucosa. The difference in mucin production contributes to the significantly enlarged cecum in B6 background mice.
π Differential Dietary Enzyme Accumulation: Accumulation of dietary enzymes in the cecal lumen differs between GF B6J and C3H mice.
Higher levels of lipase and trypsin activity in GF B6J mice, potentially influencing cecal size.
π Aging and Cecal Torsion: Aged GF B6J mice exhibit a significantly shorter lifespan due to cecal enlargement-related health issues. Cecal torsion is identified as a major health concern in aged GF animals, emphasizing the importance of genetic background considerations.
π This comprehensive study highlights the multifaceted impact of genetic background on cecal enlargement, encompassing water transport, mucin production, metabolic profiles, and health implications.
Link to the article : http://tinyurl.com/3hf7w7kz
