Merging optical images of tissue sections with the spatial distributions of molecules seen by imaging mass spectrometry is a powerful approach to better understand the metabolic roles of the mapped molecules. Here, we use histologically friendly desorption electrospray ionization-mass spectrometry (DESI-MS) to map the lipid distribution in tissue sections of ovaries from cows (N = 8), sows (N = 3), and mice (N = 12). Morphologically friendly DESI-MS imaging allows the same sections to be examined for morphological information. Independent of the species, ovarian follicles, corpora lutea, and stroma could be differentiated by principal component analysis, showing that lipid profiles are well conserved among species. As examples of specific findings, arachidonic acid and the phosphatidylinositol PI(38:4), were both found concentrated in the follicles and corpora lutea, structures that promoted ovulation and implantation, respectively. Adrenic acid was spatially located in the corpora lutea, suggesting the importance of this fatty acid in the ovary luteal phase. In summary, lipid information captured by DESI-MS imaging could be related to ovarian structures and data were all conserved among cows, sows, and mice. Further application of DESI-MS imaging to either physiological or pathophysiological models of reproductive conditions will likely expand knowledge of the roles of specific lipids and pathways in ovarian activity and mammalian fertility. Graphical abstract Desorption electrospray ionization-mass spectrometry (DESI-MS) is performed directly from frozen ovarian tissue sections placed onto glass slides. Because the desorption and ionization process of small molecules is so gentle, the tissue architecture is preserved. The sample can then be stained and tissue morphology information can be overlaid with the chemical information obtained by DESI-MS.

中文翻译：

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通过解吸电喷雾电离质谱 (DESI-MS) 成像的哺乳动物卵巢脂质分布。

将组织切片的光学图像与通过成像质谱法观察到的分子空间分布相结合是一种有效的方法，可以更好地理解映射分子的代谢作用。在这里，我们使用组织学友好的解吸电喷雾电离质谱 (DESI-MS) 来绘制奶牛 (N = 8)、母猪 (N = 3) 和小鼠 (N = 12) 卵巢组织切片中的脂质分布。形态学友好的 DESI-MS 成像允许检查相同切片的形态学信息。独立于物种，卵巢卵泡、黄体和间质可以通过主成分分析来区分，表明脂质谱在物种间保存良好。作为具体发现的例子，花生四烯酸和磷脂酰肌醇 PI(38:4)，都被发现集中在卵泡和黄体中，这两种结构分别促进排卵和着床。肾上腺酸在空间上位于黄体中，表明这种脂肪酸在卵巢黄体期中的重要性。总之，DESI-MS 成像捕获的脂质信息可能与卵巢结构有关，并且数据在奶牛、母猪和小鼠中都是保守的。将 DESI-MS 成像进一步应用于生殖条件的生理或病理生理模型，可能会扩大对特定脂质和途径在卵巢活动和哺乳动物生育能力中的作用的认识。图形摘要解吸电喷雾电离质谱法 (DESI-MS) 直接从放置在载玻片上的冷冻卵巢组织切片中进行。由于小分子的解吸和电离过程非常温和，组织结构得以保留。然后可以对样品进行染色，组织形态学信息可以与 DESI-MS 获得的化学信息叠加。