Ginkgo biloba extract (EGb 761) and a platelet-activating factor antagonist protect the retina in experimental autoimmune uveoretinitis

Oxygen-free radical toxicity is an important factor of tissue necrosis in the eye, especially in the retina. Activation of synthesis and release of platelet-activating factor (PAF) by ocular inflammatory cells and resident cells initiates cascades of mediators and cytokines which contribute to tissue damage in several ocular pathologies. The authors studied the therapeutic effectiveness of Ginkgo biloba extract (EGb 761), a potent free radical scavenger with anti-PAF activity, and of BN 50730, a specific PAF antagonist, on acute experimental autoimmune uveoretinitis induced in rats by S-antigen immunization. These treatments slightly delayed disease onset but had little effect on the severity of uveal inflammation. However, they significantly reduced inflammatory cell infiltration of the retina and the damage of the outer retinal layers. These drugs should become useful adjuvants in the therapy of posterior uveitis and other disorders that might damage the retina