Methylene blue provides behavioral and metabolic neuroprotection against optic neuropathy

Summary

This study investigated the neuroprotective effects of low-dose methylene blue in a rotenone-induced model of optic neuropathy in rats. Methylene blue, which acts as an alternative mitochondrial electron carrier, prevented retinal ganglion cell degeneration and preserved visual function by maintaining mitochondrial complex IV (cytochrome c oxidase) activity and cellular bioenergetics.

Key Findings

• Low-dose methylene blue (0.5-4 mg/kg) prevented rotenone-induced loss of retinal ganglion cells and optic nerve axons in a dose-dependent manner
• Neuroprotection was associated with preservation of mitochondrial cytochrome c oxidase (Complex IV) activity, consistent with methylene blue's role as an alternative electron carrier in the mitochondrial electron transport chain
• Treated animals maintained normal visual behavior (optokinetic responses) compared to significant impairment in untreated rotenone-exposed controls