Effects of cyclosporine in an experimental rat model of dry eye

Abstract

Purpose Dry eye syndrome is a relatively common disease with multifactorial causes. It has been shown that rodent models of dry eye experimentally induced by scopolamine, a tropane alkaloid drug with muscarinic antagonist effects, could be helpful to test and select therapeutic candidates in the disease. Here we propose to show the action of cyclosporine A, an inhibitor of T‐cell activation and inflammatory cytokine production, after oral and topical administrations. Methods Experimental dry eye was induced in female albino rats by a systemic and continuous delivery of scopolamine (20 mg/day) over 21 days via osmotic pumps implanted subcutaneously on day 1. Animals were divided in three groups of five animals: The first two groups were instilled either saline or cyclosporine 0.05% eye drops and the third group received 20mg/kg/day cyclosporine by oral administration. Tear production was measured with the phenol red thread test, tear break‐up time was studied under slit‐lamp, and corneal defects were examined by slit‐lamp observation using blue light after 0.5% fluorescein eye drop instillation and in vivo confocal microscopy. These examinations were performed in both eyes at baseline and on days 7, 14 and 21. Results Cyclosporine orally or topically administered significantly reduced clinical signs of dry eye by increasing lacrimation and decreasing corneal defect. Conclusion Cyclosporine appears to show efficacy in this model, regardless of the mode of administration. Commercial interest