Intrastromal Keratotomy with Femtosecond Laser Avoids Profibrotic TGF-β1 Induction
Investigative Ophthalmology and Visual Science
PURPOSE. To examine expression of the profibrotic cytokine TGF-␤1 after selective intrastromal corneal injury with the use of a femtosecond laser. METHODS. Rabbits underwent monocular intrastromal keratotomy at a preoperatively determined corneal depth of 160 to 200 m with the use of a femtosecond laser. Femtosecond laser-induced TGF-␤1 expression was compared in nonoperated control eyes and eyes treated with photorefractive keratectomy (PRK). Follow-up examinations were performed 1, 3, 7, and
... 8 days after surgery. TGF-␤1 protein was identified by immunofluorescence labeling. With the use of laser-capture microdissection, epithelial, stromal, and endothelial cell layers were collected, and changes in TGF-␤1 mRNA expression were quantified with quantitative RT-PCR. RESULTS. TGF-␤1 mRNA and protein expression did not significantly increase after intrastromal femtosecond laser keratotomy. In contrast, TGF-␤1 was induced in corneal epithelial and stromal cells after PRK and showed up to 23-fold higher TGF-␤1 mRNA levels compared with control corneas. The increase of TGF-␤1 mRNA levels after PRK was accompanied by increased TGF-␤1 protein production. CONCLUSIONS. Isolated stromal injury with a femtosecond laser does not result in induction of the profibrotic cytokine TGF-␤1. Because TGF-␤1 has been implicated in a fibrotic response of the corneal stroma to injury, absence of TGF-␤1 induction argues for a favorable wound-healing response. These findings support highly selective intrastromal procedures in refractive surgery. (Invest Ophthalmol Vis Sci.