Abstract
Purpose: :
To compare the mRNA expression of IL–1α, IL–8, MCP–1, and TGF–ß1 following topical ethanol treatment and mechanical debridement.
Methods: :
Fifty–eight pigmented rabbit corneas were divided into four groups. Group I (n=18) received mechanical epithelial debridement, group II (n=18) underwent 20% ethanol application for 30 seconds, and group III corneas underwent 20% ethanol application for 60 seconds. Group IV (n=4) did not undergo any procedure. Corneal epithelial and stromal keratocyte change was examined with H&E and TUNEL stains, while the mRNA expression of IL–1α, IL–8, MCP–1, and TGF–ß1 were examined with real–time polymerase chain reaction (PCR).
Results: :
Stromal keratocyte apoptosis was noticed for three days in group I and up to seven days in group III. Topical ethanol induced significant TUNEL staining of corneal epithelium and stromal keratocyte in an application time dependent manner. In group I, the expression of IL–8 mRNA showed two spikes of up–regulation on day 0 and day 5, respectively. The up–regulated mRNA expression of MCP–1, TGF–ß1, and IL–1α peaked on day 1, 0, and 5, respectively. The mRNA expression regressed to baseline on day 7. In group II and group III, the IL–8 mRNA expression was much less up–regulated than that in group I, but it also showed a small spike of up–regulation on day 5. The mRNA expression of MCP–1 and TGF–ß1was less up–regulated while there was no up–regulation of IL–1α mRNA expression throughout the experiment.
Conclusions: :
Mechanical epithelial removal induces more keratocyte apoptosis than topical ethanol application. Mechanical epithelial removal also up–regulates the inflammatory cytokine and TGF– ß1 mRNA expression.
Keywords: refractive surgery • cornea: epithelium • inflammation