A Protective Role of Coenzyme Q10 in Ethambutol-Induced Retinal Ganglion Cell Toxicity: A Randomised Controlled Trial in Mice.

Ethambutol is a widely used drug to treat tuberculosis that may cause visual disturbance including ethambutol toxic optic neuropathy (ETON). The disease disrupts bodily tissues' energy production, including the retinal ganglion cells (RGC). Many have proposed treatment with coenzyme Q10 (coQ10) due to its antioxidant and facilitative effects that can improve mitochondrial electron transport. The present study hence assessed whether coQ10 could protect against ETON through a parallel triple-blinded randomised controlled trial in 18 mice using computer-generated tables for treatment allocation. All of the mice received 25 mg/kg ethambutol daily, while only nine in the treated group also received 100 mg/kg coQ10. After 30 days, blinded pathologists counted RGC numbers in enucleated and dyed orbital tissue. The treated group had significantly denser RGCs at 47.2 (standard deviation [SD] 10.6) cells per 500 µm microscope field vs 33.5 (SD 6.3) in the control group (t = 3.34, p = .004). CoQ10 therefore protected RGCs from ETON. Clinical trials of coQ10 in human subjects treated with ethambutol should be considered.