Characterization of T lymphocyte subtypes in endotoxin-induced uveitis and effect of pentoxifylline treatment

Evaluation of intravitreal injection of pentoxifylline in experimental endotoxin-induced uveitis in rabbits

The objective of the present study was to investigate the clinical and histopathological effects of intravitreal injection of pentoxifylline (PTX) the management of an experimental model of uveitis. Fifty-two rabbits were divided randomly into six intravitreal treated groups as below: 1) Balanced salt solution (BSS), 2) Salmonella typhimurium lipopolysaccharide endotoxin (LPS) + BSS, 3) LPS + PTX 100 μg, 4) LPS + PTX 500 μg, 5) BSS + PTX 100 μg and 6) BSS + PTX 500 μg. Inflammation was evaluated by clinical examinations using slit lamp on days 1, 3, 5 and 7 post injections and histopathological examinations were also performed at the end of the study. Clinical examinations demonstrated a statistically significant difference between group 1 and group 2 on day 5 and day 7. Moreover, the comparison of clinical severity scores of group 1 with groups 3, 4, 5 and 6, on third, fifth and seventh post-injection days showed statistically significant differences. The mean histopathological inflammation intensity score in groups 5 and 6 was significantly higher than group 1. The mean histopathological inflammation intensity score in groups 3, 4, 5 and 6 was significantly higher than group 2. Intravitreal injection of PTX in an experimental model of uveitis in rabbits not only does not reduce inflammation but also leads to inflammation when used alone or in combination with LPS.

Resolvin D1 reduces the immunoinflammatory response of the rat eye following uveitis

This study investigated whether the administration of resolvin D1 to rats with endotoxininduced uveitis (EIU) ameliorates the immuno-inflammatory profile of the eye. 24 h after the administration of 200 μg LPS into the footpad of Sprague-Dawley rats, severe changes of the structure of the eye occurred concomitantly with a severe inflammatory and immune response. These latter included strong infiltration of PMN leukocytes CD11b(+) T-lymphocytes CD4(+) and CD8(+) within the eye and a significant release of the cytokines/chemokines TNF-alpha, CXCL8, and RANTES too. Bolus of resolvin D1 (RvD1; 10-100-1000 ng/kg in 200 μL of sterile saline via the tail vein) significantly and dose-dependently (i) reduced the development of the ocular derangement caused by LPS; (ii) reduced the clinical score attributed to EIU; (iii) reduced the protein concentration and myeloperoxidase activity (MPO) in aqueous humor (AqH); and (iv) reduced neutrophils, T-lymphocytes, and cytokines within the eye.

NK1.1 Cells Downregulate Murine Endotoxin-Induced Uveitis Following Intraocular Administration of Interleukin-12

To evaluate the role of IFN-gamma (interferon gamma) in IL-12- (interleukin-12)-induced inhibition of the inflammatory response in the eye during endotoxin-induced uveitis (EIU). C57BL/6 wild type mice and IFN-gamma-deficient (GKO) mice were injected with 250 microg of Salmonella typhymurium endotoxin as a model for EIU. Animals were then injected intraocularly with 100 ng of rIL-12 or the equivalent volume of Phosphate-buffer saline (PBS). Histopathologic grading of disease was performed 12, 36 and 72 h after endotoxin injection. Chemokine mRNA expression in the eye was evaluated by reverse transcriptase-polymerase chain reaction. Depletion of NK1.1+ cells in vivo was performed using a PK136 antibody. Depletion of IFN-gamma was performed using the R4-6A2 antibody. C57BL/6 mice treated with rIL-12 intraocularly were protected from the development of EIU. Neutralization of IFN-gamma with a monoclonal antibody abrogated such protection. The IL-12 protective effects were lost in NK1.1-depleted mice. Intraocular IL-12 decreased the expression of keratinocyte-derived chemokines (KC) gene but had no effect on macrophage inflammatory protein (MIP-2) gene. The protective effect of IL-12 during EIU occurs through production of IFN-gamma by NK1.1+ cells. IL-12-induced higher levels of IFN-gamma are also correlated with lower expression of the chemokine KC, resulting in diminished attraction of neutrophils to the inflammatory site.

Etanercept treatment in the endotoxin-induced uveitis of rats

This study was conducted to investigate therapeutic value of a soluble tumor necrosis factor-alpha (TNF-alpha) receptor, etanercept, in a rat model of endotoxin-induced uveitis (EIU). Forty-two inbred male Lewis rats were divided into seven equal groups. 200 microg of Escherichia coli 055:B55 lipopolysaccharide (LPS) was injected in one hind footpad of the Groups 2, 3, 4, 5, 6, and 7 rats. Group 5, 6, and 7 rats also received subcutaneous etanercept 24 hr prior to LPS injection at a dose of 0.4 mg kg(-1). Group 1 rats were used as controls. Eight, 24, and 48 hr after treatment clinical uveitis scores (miosis, iris hyperemia, and hypopyon) were assessed by a masked observer and the rats were euthanized. Neutrophil leukocytes, CD8+, CD4+, and CD45RO+ cells in the anterior uveal tissue were counted either after hematoxylin-eosin or monoclonal antibody staining. TNF-alpha levels were also measured in the aqueous humor samples by an ELISA method. Etanercept treatment significantly improved clinical uveitis scores at all examination points compared to the LPS injected animals. The improvement was almost complete expect for the miosis score, since no significant difference was detected between the controls and LPS + Etanercept treated animals at all examination points. Cell counts were also at significantly lower levels in LPS + Etanercept treated animals at all examination points, except for CD8+ and CD45RO+ cell counts at 24 hr examination point. There was no significant difference between the controls and LPS + Etanercept treated animals at all examination points as with CD4+ and CD45RO+ cell counts at 48 hr. Our data showed that etanercept had a definite effect on the treatment of EIU. Further studies should clarify its efficacy on clinical uveitis conditions.