Journal: Aging Cell

Article Title: The MICOS Complex Regulates Mitochondrial Structure and Oxidative Stress During Age‐Dependent Structural Deficits in the Kidney

doi: 10.1111/acel.70534

Figure Lengend Snippet: Age‐associated histological and ultrastructural remodeling of renal mitochondria in mice. (A, B) Representative images of Masson's trichrome staining of the kidney cortex from young (4–5 months) and old (21–23 months) mice. Insets show higher‐magnification views of glomerular and tubular regions. (A′, B′) Representative immunohistochemistry for nitrotyrosine (brown) in the kidney cortex from young (4–5 months) and old (21–23 months) mice. (C) Quantification of trichrome‐positive area (%) and (D) nitrotyrosine staining intensity corresponding to panels A′ and B′. (E–E″) Representative transmission electron microscopy (TEM) images of kidney tissue from 3‐month‐old male mice and (F–F″) 2‐year‐old male mice, showing mitochondrial ultrastructure at increasing magnifications. (G, H) Representative serial block‐face scanning electron microscopy (SBF‐SEM) images illustrating three‐dimensional cristae morphology in 3‐month‐old and 2‐year‐old samples, respectively. Boxed regions indicate mitochondria selected for cristae segmentation and magnified in (G′–G″) and (H′–H″). Quantifications in panels I–L were derived from TEM images, whereas cristae morphometric parameters in panels M–O were obtained from three‐dimensional SBF‐SEM reconstructions. (I) Quantification of mitochondrial number (J), mitochondrial area (K), circularity index (L), and cristae score, a semiquantitative measure of observed cristae organization. (M) Cristae area, (N) cristae volume, and (O) cristae perimeter derived from three‐dimensional reconstructions. Mitochondrial measurements were obtained from approximately 1050 mitochondria at 3 months and approximately 1450 mitochondria at 2 years. Cristae score analysis included 1093 mitochondria. Each dot represents an individual mitochondrion, with variable numbers per animal. For TEM‐based analyses, each age group comprised 3 mice. Data are presented as mean ± SEM. Statistical comparisons were performed using Mann–Whitney U tests. Statistical significance is denoted as ns (not significant), p < 0.05, p < 0.01, and ** p ≤ 0.0001.

Article Snippet: A serial block face‐scanning electron microscope and manual segmentation using the Amira software were employed to visualize murine kidney samples during the aging process at 3 months (young) and 2 years (old).

Techniques: Staining, Immunohistochemistry, Transmission Assay, Electron Microscopy, Blocking Assay, Derivative Assay, MANN-WHITNEY