Synthetic Glucocorticoid-Induced Leucine Zipper Peptide Inhibits Lipopolysaccharide-Induced Ocular Inflammation in Rats

Purpose: To demonstrate the anti-inflammatory action of a synthetic glucocorticoid-induced leucine zipper (GILZ(98-134)) peptide (GILZ-p) in a model of endotoxin-induced uveitis (EIU) in rats. Methods: The EIU model was induced in Sprague Dawley rats with an intravitreal injection of lipopolysaccharide (LPS). Synthetic GILZ-p was injected intravitreally 6 h after the LPS injection. To evaluate the anti-inflammatory effects of GILZ-p, the inflammatory response in the anterior chamber and iris of the rat eyes was evaluated with a slitlamp microscope on days 0, 1, 2, 3, and 4 after GILZ-p injection. The retinal expression of inflammatory cytokines was measured on days 0, 1, 2, 3, and 4 after GILZ-p injection. Muller cell gliosis was also detected at planned time points after GILZ-p injection. Results: Anterior segment inflammation peaked at 24 h after LPS injection in the EIU model. Compared with the controls, intravitreal GILZ-p significantly suppressed LPS-induced anterior segment inflammation in the EIU rats. The levels of retinal inflammatory factors IL-1 beta, TNF-alpha, MCP-1, and ICAM-1 were simultaneously reduced by the intravitreal GILZ-p injection. The expression of vimentin in the EIU retina was significantly reduced by GILZ-p, and the downregulated aquaporin 4 in the EIU retina was significantly restored by GILZ-p. Conclusion: The synthetic GILZ-p inhibited the inflammatory reaction in the EIU model and may have utility in the treatment of inflammatory ocular disease.