DataSheet_1_Mast Cells Are Identified in the Lung Parenchyma of Wild Mice, Which Can Be Recapitulated in Naturalized Laboratory Mice.pdf

BackgroundIt is well documented that laboratory mice bred and maintained in ultra-hygienic specific pathogen-free (SPF) barriers display reduced richness and complexity of microbiota compared with wild mice. The laboratory mice profoundly lack lung parenchymal mast cells. Hence, we aimed to investigate the lung distribution of mast cells in free-living wild mice.MethodsWild house mice were trapped in South-Eastern Norway and Hemtabad, West Bengal, India. C57BL/6 laboratory mice were bred in a purposefully built, closed environment with bedding material obtained from the natural environment in order to normalize the gut microbiota of these laboratory mice to that of the wild mice, and the offspring were collected for study at eight weeks of age.ResultsMast cells were easily identified at a substantial density in the lung parenchymal tissues of wild mice from both Norway and India, which stands in clear contrast to the rare distribution of lung parenchymal mast cells in the conventional laboratory SPF mice. Consistently, wild mice also expressed higher pulmonary levels of stem cell factor, a critical growth factor for mast cell survival. Higher levels of histamine were recorded in the lung tissues of the wild mice. Interestingly, “naturalized” C57BL/6 laboratory mice which spent their entire life in a semi-natural environment developed lung parenchymal mast cells at an appreciable density.ConclusionOur observations support that environmental factors, possibly through modulation of microbiota, may impact the tissue distribution of mast cells in mouse lung parenchyma.

背景：关于在超洁净的特定病原体无SPF屏障中培育和维护的实验室小鼠与野生小鼠相比，其微生物群的丰富度和复杂性显著降低的事实，已有大量文献记载。实验室小鼠在肺实质中缺乏浆细胞。因此，本研究旨在调查自由生活的野生小鼠中浆细胞的肺分布情况。
方法：在挪威东南部和印度西孟加拉邦的Hemtabad捕获野生家鼠。在有意构建的封闭环境中培育C57BL/6实验室小鼠，其垫料材料来源于自然环境，以使这些实验室小鼠的肠道微生物群正常化，并与野生小鼠的微生物群相似，并在八周大时收集后代进行研究。
结果：在挪威和印度野生小鼠的肺实质组织中，浆细胞以显著密度易于识别，这与传统实验室SPF小鼠中肺实质浆细胞的罕见分布形成鲜明对比。一致的是，野生小鼠也表现出更高的肺泡干细胞因子水平，这是浆细胞生存的关键生长因子。在野生小鼠的肺组织中记录到更高水平的组胺。有趣的是，在半自然环境中度过其整个生命周期的“自然化”C57BL/6实验室小鼠，其肺实质中浆细胞的密度也是可观的。
结论：我们的观察结果表明，环境因素，可能通过调节微生物群，可能影响小鼠肺实质中浆细胞的组织分布。