Experimental auto-immune uveitis (EAU), an animal model for human ocular inflammation, can be induced by the injection of a soluble retinal-s antigen. This experimental model will be useful in the study of the pathophysiology of uveitic diseases, for epidemiological studies and for therapeutic trials of new drugs for uveitis. This paper sought to isolate, characterize and purify the retinal-s antigen from pigs, and to induce and demonstrate EAU in female albino rats. A total of 36 retinas from pigs were separated from the underlying pigment epithelium and choroid. Fractionation was done using 0.01 M sodium potassium phosphate buffer, pH 7.2. About 200 microliters of retinal extracts were treated with sodium dodecyl sulfate then run in electrophoresis using 10% acrylamide gels. Induction of EAU in the female albino rats were performed through light microscopy and ultra-structural analyses. The gel filtration profile showed several protein peaks of various molecular weights. Two of these peaks, I and III presented uveitogenic properties. Gel electrophoresis profile showed that protein peak III have protein bands similar to the pattern exhibited by the standard retinal s-antigen. In light microscopic studies, the control rat did not show any indication of ocular inflammation. However, two rats which had received an injection of pooled fractions corresponding to protein peaks I and III exhibited signs of ocular inflammation similar to those in the s-antigen standard induced-uveitic eye. This was also demonstrated in ultra-structural studies. The study suggests that the preparation of s-antigen following the procedure of Dorey et al is comparable to the standard obtained from Alco Laboratories. The authors conclude that future experiment can be carried out utilizing the supply of retinal s-antigen prepared locally.
The study aims to: (1) isolate, characterize and purify the retinal s-antigen; (2) induce experimental auto-immune uveitis (EAU) in female albino rats; (3) demonstrate histopathologically the presence of EAU.