Preventing Axonal Sodium Overload or Mitochondrial Calcium Uptake Protects Axonal Mitochondria from Oxidative Stress-Induced Alterations

Figure 1

Blocking axonal Na⁺ influx with tetrodotoxin (TTX) prevents oxidative stress-induced mitochondrial morphology alterations. (a) Representative original images of all different experimental conditions; axons incubated with aCSF alone contained elongated mitochondria; incubation with 100 μM H₂O₂ led to the generation of smaller and rounder mitochondria, and some diffuse MitoTracker® distribution; axon simultaneously incubated with 100 μM H₂O₂ and 100 nM TTX contained elongated mitochondria; axon simultaneously incubated with 100 μM H₂O₂ and 1 μM TTX contained short mitochondria but with increased area. (b–d) Shape factor (b), length (c), and area (d) of mitochondria located near the nodes of Ranvier in axons incubated with the above-mentioned treatments. Nodes of Ranvier are marked with a red “i”. , , , and . The error bars represent the standard error of mean; animals and 22 roots; untreated 7 roots, H₂O₂ 6 roots, H₂O₂+100 nM TTX 4 roots, and H₂O₂+1 μM TTX 5 roots.

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