MIMS analysis of cells and structures across ovarian tissue sections.
(A) Diagram depicting and defining structures of the mammalian ovary. (B) Representative hue saturation intensity (HSI) mosaic from an ovary of a 15N labeled mouse (6 months old). Localization and abundance of 15N varied depending on cell type. HSI scale was set to 0% (natural 15N/14N ratio) to 300% (above the natural ratio). Scale bar = 60 µm. (C) High abundance of 15N is seen in early-stage follicles, specifically within granulosa cells. (D) Representative images of somatic cells show differences in 15N labeling. (E) Intracellular abundance of 15N is colocalized with 31P abundance across all cell types. (F) Differences in 15N/14N ratios reveal granulosa cells of early-stage follicles have greater 15N abundance than later stages. (G) Among somatic cells, quantitative analysis shows a greater abundance of 15N at the ovarian surface epithelium. (H) Ratio analysis show abundance of 15N localized in nuclear regions of cells. A hypothetical ratio of one, denoted as a red dash line, signifies no difference in 15N abundance between cytoplasmic and nuclear regions. Abbreviations: PM (primordial follicle), 1° (primary follicle), 2° (secondary follicle), AF (antral follicle), CL (corpus luteum), TC (theca cell), ST (stroma), and OSE (ovarian surface epithelium). HSI scale for all images was set to 0%-300% (above natural abundance). Data are shown as mean±SEM. Statistical analysis was performed using a one-way ANOVA. Asterisk denotes statistical significance (* p≤.05; ** p≤.01; *** p≤.001; **** p≤.0001). Scale bar = (B): 50 µm; (C): 3 µm (PR), 6 µm (1°), 30 µm (2°), 75 µm (AF); (D): 2.5 µm (CL), 2.5 µm (TC), 5 µm (ST), 2.5 µm (OSE); (E): 3 µm (GC), 3 µm (TC), 2.5 µm (ST), 6 µm (OSE).