Figure 1: Mitochondrial injury in the spinal cord p.i. was detected by EM. (a) Normal group, (b) 3-day group, (c) 7-day group, (d) 16-day group, and (e) 30-day group. Arrows indicate mitochondrial injury ((a)–(e)) and axoplasmic atrophy (d); scale bar = 1  m. The morphology of mitochondria, myelin sheath, and axons was normal in the normal group (a). Swollen mitochondria and compressed crista can be observed with normal myelin sheath and axons in the 3-day and 7-day groups ((b)-(c)). Mitochondria are shown with swelling, reduction of mitochondrial crest, and matrix density or vacuolation in the 16-day group. Demyelination and axoplasmic atrophy can also be observed (d). Mild alleviation of lesions is observed in the 30-day group (e) compared to the 16-day group.