Retinal toxicity of intravitreal rituximab in albino rabbits

To evaluate retinal toxicity of intravitreal rituximab.

Twelve albino rabbits were included in the study. 1 mg/0.1 mL of rituximab was injected to the right (experimental) eye of each rabbit, and 0.1 mL of saline was injected into the left (control) eye. Electroretinogram was recorded before injection and 3 hours, 4 days, 1 week, 2 weeks and 4 weeks after injection (12 rabbits), and visual evoked potential was recorded before injection and 4 weeks after injection (10 rabbits). Histology and glial fibrillary acidic protein immunocytochemistry (12 rabbits) were performed at 4 weeks after injection. Clinical examination was conducted at all time points in all rabbits.

The average dark-adapted electroretinogram b-wave Vmax ratios, and the average light-adapted b-wave amplitude ratios were approximately 1, and the average log σ difference was around zero throughout the follow-up period. The average visual evoked potential amplitude ratio and the average visual evoked potential implicit time difference were approximately 1 and 0, respectively. No histologic damage was seen, but glial fibrillary acidic protein was mildly expressed in 6 of 12 experimental eyes. Results of clinical examination were normal in all the eyes.

Intravitreal injection of 1 mg rituximab does not cause functional or histologic signs of retinal toxicity in albino rabbits. Mild glial fibrillary acidic protein expression in Müller cells probably indicates a mild degree of retinal stress.