Background: The retinal pathophysiology of methanol intoxication is that formate inhibits retinal mitochondrial function and increases oxidative stress.
Objective: To investigate the effect of coenzyme Q10 and curcumin on chronic methanol intoxication causing retinopathy in rats.
Material and Method: The authors designed an experimental study of chronic methanol intoxication in rats depleted of folate with methotrexate. The studied group received methanol (2 mg/kg body weight in saline by intraperitoneal injection) and methotrexate (0.1 mg/kg body weight in saline by subcutaneous injection) every other day for ten weeks to induce chronic methanol intoxication, while another group received saline as vehicle and served as control group. The studied rats were confirmed to develop significant retinopathy after 10 weeks and then assigned to three treatment arms: either corn oil (as control) or coenzyme Q10 (20 mg/kg/day) or Curcuma longa extract (2.5 mg/kg/day) for four weeks. Eyes were enucleated and the retinal tissue was prepared for histological examination. The sections were evaluated by an experienced pathologist and blinded to the experimental conditions.
Results: Histological analysis revealed that animals treated with both methanol and methotrexate showed vacuolation of photoreceptor inner segment and disaggregation of cells in the inner and outer nuclear layers of the retina compared to a normal histological appearance in control animals. The retinal histology in the experimental animals with administration of Coenzyme Q10 or Curcuma longa extract appeared essentially normal and this was not found in the experimental animals which received corn oil.
Conclusion: Coenzyme Q10 and curcumin administration improves retinal histology by reversing the pathological changes due to chronic methanol and establish a morphologically normal retina.

Keywords: Methanol, Coenzyme Q10, Curcumin, Retinopathy, Optic neuropathy