Effects of oligomycin, CsA, and collagen VI on mitochondrial ultrastructure in healthy donor and UCMD patient cell cultures. (A) Electron micrographs of myoblasts from a healthy donor (a–c) and UCMD patient 2 (d–f) plated on plastic in the absence (a and d) or presence of 6 μM oligomycin (b and e) or 6 μM oligomycin plus 1.6 μM CsA (c and f). (Scale bar, 400 nm.) (B) Percentage of cells with swollen mitochondria in the myoblasts of a healthy donor (CTRL) or UCMD patients 1, 2, and 3 (P1–P3) plated on plastic in the absence (Basal) or presence of 6 μM oligomycin (Oligo), 1.6 μM CsA, or both or of the same cells plated on collagen VI (COLVI). Data are the mean of three independent experiments ± SD.