Figure 5. Electron microscopy reveals that SS-31 treatment preserves mitochondrial morphology.

(a) Chondrocytes in an untreated, non-impact sample display normal, elongated mitochondrial morphology (top) and well-defined cristae structure (bottom). (b) After impact, untreated mitochondria appear ovate and lack cristae structure. (c) In contrast, samples treated with SS-31 have normal mitochondrial morphology with preserved cristae structure after impact. For imaging, samples were fixed 30 minutes after impact and images were collected in locations directly under the impact, corresponding to the imaging locations outlined in Figure 1c. Text and arrow labels on each image indicate extracellular matrix (“ECM”), mitochondria (“MT”), nucleus (“N”), and cristae (“C”). In low magnification images (top row) scale bar indicates 600 nm. In high magnification images (bottom row) scale bar indicates 200 nm.