Trisomy fibroblasts showed increased oxidative stress and accumulation of damaged mitochondria.

(A) Relative ROS production as expressed by relative MitoSOX/MitoTracker ratio (n = 5–6 per cell line). *P < 0.05. Dip, diploid; Tri, trisomy. (B) Relative mitochondrial mass per cell as assessed by average TOM20-positive area per cell. The upper panels show representative phase contrast images in which mitochondria were stained with MitoTracker. Bar = 50 μm. The lower panel shows corresponding quantification (n = 3–8 per cell line). **P < 0.01. Dip, diploid; Tri, trisomy. (C) Relative mitochondrial membrane potential per cell (n = 5–10 per cell line). **P < 0.01. Dip, diploid; Tri, trisomy. Comparisons were made by Student’s t-test.