Background Research determined that TLR4 is positively expressed on the macrophages in iris and ciliary in acute endotoxin-induced uveitis(EIU),indicating that TLR4 participated in the pathogenesis of the anterior uveitis.Objective The aim of this study is to observe the expressions of toll-like receptor-4(TLR4),Myeloid differentiation factor 88(MyD88),NF-κB p65 in iris tissue in the eyes with endotoxin-induced acute anterior uveitis.Methods Animal models of acute anterior uveitis were established by a hind footpad injection of 200μg Cholera vibrio LPS in 40 SPF Wistar rats with the age of 6-8 weeks.Other 10 age-matched rats were as normal controls.Ocular inflammation was examined under the slit lamp microscope at the 2-hour interval after the injection and intensity of inflammation was scored according to the standard of Lajavardi[4].Histopathology examination was performed for the evaluation of inflammatory reaction of iris and ciliary tissues by HE staining at 24 hours after LPS injection.Expressions of TLR4,MyD88 and NF-κB p65 in iris and ciliary body tissue were detected through immunohistochemistry.TLR4~+,MyD88~+ and NF-κB p65~+ cells were counted.Results The inflammatory reaction was gradually enhanced after injection of LPS and peaked at 24 hours and allivated 48 hours later.The infiltration of lots of inflammatory cells and fibrinous exudate were exhibited in the anterior chamber,posterior chamber,iris and ciliary tissue under the optical microscope at 24 hours after injection of LPS.No positive expressions of TLR4,MyD88 and NF-κB p65 in iris-ciliary body complex were found in normal control rats.The positive cells for TLR4,MyD88 and NF-κB p65 in iris-ciliary body complex were significantly different among 12 hours group,48 hours group and 72 hours groups(F=46.79,P＜0.05;F=54.37,P＜0.05;F=85.32,P＜0.05),and the positive cells for TLR4,MyD88 and NF-κB p65 peaked at 24 hours after injection of LPS.Conclusion The expression of TLR4 and its downstream signal transduction molecules MyD88,NF-κB p65 vary in uvea during EIU,indicating the potential role of LR4-MyD88 dependent pathway in the pathogenesis of acute anterior uveitis.

BACKGROUNDT-cell receptor (TCR) plays an important role in the development of autoimmune diseases. Recently, it was reported that immunization of animals with TCR peptide derived from the pathogenic cells could prevent autoimmune diseases. The aim of this study was to investigate whether vaccination with a synthetic peptide from the hypervariable region of TCR V(beta) 8.3, an experimental autoimmune uveoretinitis (EAU)-associated gene, was able to prevent the disease.

METHODSEAU was induced in Lewis rats by immunization with IRBP R16 peptide emulsified in complete Freund's adjuvant (CFA). The clinical and histological appearances were scored. Delayed type hypersensitivity (DTH) and lymphocyte proliferation were detected. Cytokine levels of aqueous humour, supernatants of cells from spleen and draining lymph nodes were measured by enzyme linked immunosorbent assay (ELISA). Gene expression of TCR V(beta) 8.3 on CD(4)(+) T cells was examined by real time quantitative polymerase chain reaction (PCR).

RESULTSAfter vaccination, the intraocular inflammation was significantly mitigated, antigen specific DTH and lymphocyte proliferation responses were suppressed, interleukin (IL)-2 in aqueous humour, interferon (IFN)-gamma and IL-2 produced by the spleen and draining lymph node cells were significantly decreased, whereas the production of IL-4 and IL-10 were increased. The response of draining lymph node cells to TCR V(beta) 8.3 peptide was enhanced after vaccination. Inoculation with CFA alone did not affect the severity of EAU and the above parameters. The suppression of EAU was much stronger in the group of four fold inoculations than the group of two fold inoculations. The expression of TCR V(beta) 8.3 gene was significantly reduced in the group of fourfold inoculations.

CONCLUSIONVaccination with the synthetic TCR V(beta) 8.3 peptide could remarkably inhibit the development of EAU.

Animals ; Autoimmune Diseases ; prevention & control ; Cytokines ; biosynthesis ; Female ; Genes, T-Cell Receptor beta ; Rats ; Rats, Inbred Lew ; Receptors, Antigen, T-Cell, alpha-beta ; immunology ; Retinitis ; prevention & control ; Retinol-Binding Proteins ; immunology ; Th1 Cells ; immunology ; Th2 Cells ; immunology ; Uveitis ; prevention & control ; Vaccination