Characterization and comparison of human and mouse milk cells

Recent data has characterized human milk cells with unprecedented detail and provided insight into cell populations. While such analysis of freshly expressed human milk has been possible, studies of cell functionality within the infant have been limited to animal models. One commonly used animal model for milk research is the mouse; however, limited data are available describing the composition of mouse milk. In particular, the maternal cells of mouse milk have not been previously characterized in detail, in part due to the difficulty in collecting sufficient volumes of mouse milk. In this study, we have established a method to collect high volumes of mouse milk, isolate cells, and compare the cell counts and types to human milk. Surprisingly, we found that mouse milk cell density is three orders of magnitude higher than human milk. The cell types present in the milk of mice and humans are similar, broadly consisting of mammary epithelial cells and immune cells. These results provide a basis of comparison for mouse and human milk cells and will inform the most appropriate uses of mouse models for the study of human phenomena.

既往研究已以前所未有的精细程度对人乳细胞进行了表征，并对其细胞群构成提供了深入见解。尽管针对新鲜挤出人乳的此类分析已可实现，但关于婴儿体内乳源细胞功能的研究仍仅能依托动物模型开展。小鼠是乳腺与乳研究领域常用的动物模型，但目前公开的小鼠乳组成相关数据仍十分有限。具体而言，此前尚未对小鼠乳中的母体来源细胞进行细致表征，这在一定程度上源于难以收集足量的小鼠乳。本研究建立了高效收集大量小鼠乳的方法，完成细胞分离后将其细胞计数与细胞类型与人乳进行了对比分析。令人意外的是，我们发现小鼠乳的细胞密度较人乳高出三个数量级。小鼠与人类乳中的细胞类型整体相似，主要包含乳腺上皮细胞（mammary epithelial cells）与免疫细胞。本研究结果为小鼠乳与人乳细胞的对比研究提供了参照基准，同时也将为选择适配的小鼠模型开展人类相关生理现象研究提供指导依据。