Ocular safety of infliximab in rabbit and cell culture models

Purpose: To undertake the safety testing of infliximab in animal and cell culture models. Methods: Sixteen New Zealand albino rabbits were divided into 4 groups of 4 animals. Each group received 2 mg of infliximab in the right eye and saline solution in the left eye. Clinical examination and retinal histology were performed at months 1, 2, and 3 for groups A, B, and C, respectively. Electroretinography (ERG) recordings were made before the injection, and at months 1 and 2 for group D. The assessment of the safety of infliximab in retinal pigment epithelial (RPE) and retinal ganglion (RGC-5) cells was performed by Western blot analysis of caspase-3 involved in apoptosis pathway, the analysis of cytotoxicity of infliximab by WST-1 proliferation assay, and time-lapse video-microscopy to register the morphology of treated cells in time-lapse. Results: Clinical examination of the eyes, histological study of the retina, and ERG recordings showed no sign of ocular toxicity after a single intravitreal injection of 2 mg of infliximab in the rabbit model. RPE and RGC viability was not reduced either in the range of concentration (up to 3 mg) or during the follow-up interval. Conclusion: This study suggests that infliximab has no direct retinal toxicity using rabbit (2 mg) and cell culture (2 and 3 mg) models.