File:CYP46A1 expression and cholesterol content in aged mouse cochlea.png

English: "(A) Representative confocal images in the xy projection of whole mounts organ of Corti from the medial region immunolabeled for CYP46A1 (green) and calretinin (red) from young (top) and old (bottom) C57BL/6J mice (scale bar = 30 μm). Filled arrows indicate the SCs’ area. Arrowheads point to surviving OHCs in aged mice. IHCs and OHCs’ area are also indicated. (B) Quantitative data obtained from young (n = 5) and aged (n = 6) mice. CYP46A1 fluorescence intensity (a.u., arbitrary units) was measured in IHCs (left), OHCs (middle), and SCs (right) at 2 months and 2 years of age at 3 regions of the cochlea: apical, medial, and basal end (Young: n = 43 IHCs, 78 OHCs, and 144 SCs at the apical; 25 IHCs, 29 OHCs, and 51 SCs at the medial; and 12 IHCs, 31 OHCs, and 24 SCs at the basal region. Old: n = 22 IHCs, 28 OHCs, and 55 SCs at the apical; 24 IHCs, 17 OHCs, and 79 SCs at the medial; and 28 IHCs, 13 OHCs, and 69 SCs at the basal region). Examples of ROIs that correspond to each cellular type (IHC, OHC, and SC) were drawn. In aged mice, there was a significant increase in CYP46A1 immunolabeling in IHCs, OHCs, and SCs compared to young ears at all the cochlear regions (except at the apical end in SCs). n.s. = not significant. Asterisks represent the statistical significance (t test, ** = p < 0.01, *** = p < 0.001 **** = p < 0.0001). (C) Representative confocal images of whole mounts organ of Corti from the medial region of the cochlea stained for filipin to label cholesterol (green) and phalloidin for visualizing actin in stereocilia (blue) from young (top) and old (bottom) C57BL/J mice (scale bar = 30 μm). Rectangles indicate the region of the zoomed-in areas shown on the right using a 63× objective (scale bar = 8 μm). Pink dotted lines represent the diameter of individual IHC and OHC. (D) Filipin staining quantified with a pixel intensity graph (a.u., arbitrary units) along a line (shown as dotted pink lines in panel C) crossing either individual OHCs or IHC in young (n = 3) and aged (n = 6) mice at all the regions of the cochlea. In aged mice, there was a significant reduction in cholesterol content in IHCs (top panel) and surviving OHCs (bottom panel) compared to young ears (Young: n = 104 IHCs and 200 OHCs; Old: n = 52 IHCs and 22 OHCs). Asterisks represent the statistical significance (t test, **** = p < 0.0001). The data underlying this figure can be found at https://osf.io/xpemk/. IHC, inner hair cell; OHC, outer hair cell; ROI, region of interest; SC, supporting cell."