Abstract
Purpose: :
Endotoxin-induced uveitis (EIU) serves as an experimental animal model for acute anterior uveitis in humans. In this study, we evaluated the temporal expression profile of several key proinflammatory cytokines following EIU in C57BL6 mice. We also further validated the model with Predforte, the standard treatment option for human patients with uveitis.
Methods: :
EIU was induced with a subcutaneous injection of 200 ug lipopolysaccharide (LPS) into the hind footpad of 6-8 week old C57BL6 mice. Control mice received PBS injections. Retinas were collected 2, 4, 6, 8, 12, and 24 hours after injection and snap frozen for cytokine analysis. The levels of proinflammatory cytokines and cell adhesion molecules in retinal lysates were quantified either by ELISA (ICAM) or cytokine bead array (CBA) analysis (MCP-1, IL-6, TNF-alpha, IL-12p70, and IL-10) and normalized to total retinal protein. To test the effects of a known anti-inflammatory drug in this mouse model, a 5 ul drop of Predforte was given every hour starting 4 hours before LPS injection, and continuing until study termination. Three hours after LPS injection, retinas were harvested and evaluated for TNF-alpha, MCP-1, and IL-6 by CBA analysis.
Results: :
TNF-alpha expression in the retina peaked 2 hours after LPS injection, whereas IL-6 levels were highest 4 hours after injection. A robust response was observed for MCP-1 after 2 hours which remained high 24 hours after LPS injection. ICAM levels peaked between 8 and 12 hours, and then leveled off, whereas IL-12 and IL-10 were unaffected by LPS. Topical dosing of Predforte reduced the severity of the EIU, as evidenced by a statistically significant reduction in IL-6, MCP-1, and TNF-alpha.
Conclusions: :
We have further characterized and optimized the C57BL6 mouse model of EIU by demonstrating differences in peak expression times of various proinflammatory cytokines following LPS injection. Our results enable the selection of the optimal tissue harvest time following LPS injection for the evaluation of specific cytokines and cell adhesion molecules as markers of disease progression in C57BL6 mice.
Keywords: uveitis-clinical/animal model • cytokines/chemokines • inflammation