Abstract
Purpose: :
The outcome of keratorefractive procedures such as PRK and LASIK is limited by the corneal stromal wound–healing process, which can give rise to complications such as haze formation and regression. Corticosteroids are normally used in the post–operative follow–up period, however the cytokine production by corneal stromal fibroblasts after photo–ablation is not well defined.
Methods: :
Quiescent cultured human corneal stromal fibroblasts (HCF) at confluence were treated with photoablation. Two laser treatments of equal energy were given to three wells of each of two HCF cultures. Culture medium was collected before treatment, and after 1 and 24 hours. Cell count was performed at each time point. Concentrations of IL–1–α, –2, –4, –5, –6, –8, –10, –12, –13, IFN–γ, TNF–α, eotaxin, RANTES and MCP–1 were determined using multiplexed bead analysis. Samples were incubated with a cocktail of LuminexTM beads, each coated with an individual monoclonal anti–cytokine/chemokine antibody, followed by biotinylated polyclonal antibodies and streptavidin–phycoerythrin. The fluorescence intensity of each bead population was measured using a Luminex100TM.
Results: :
Culture medium of HCF at baseline contained high levels of IL–6, IL–8 and MCP–1, and lower but still detectable levels of IL–1, –6, –8, MCP–1, RANTES and eotaxin. One hour after laser treatment, level of all detected cytokines in culture medium were reduced. However, at 24 hours, IL–6, IL–8 and MCP–1 levels were significantly increased compared to baseline, while IL–1, RANTES and eotaxin levels had returned to baseline levels. IL–2, –4, –5, –10, –13, IFN–γ and TNF–α were not detected in culture medium either before or after in vitro photoablation.
Conclusions: :
Photorefractive procedures activate stromal corneal fibroblasts to produce multiple cytokines and chemokines that may modulate would healing and also induce severe inflammation.
Keywords: refractive surgery • inflammation • wound healing