Abstract

P 148

Intrastromal Keratotomy with Femtosecond Laser avoids profibrotic TGF-beta1 induction

Christian Meltendorf1, Guido Burbach2, Thomas Deller3
1Universitätsklinik und Poliklinik für Augenheilkunde, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, 2Klinik für Dermatologie, Venerologie und Allergologie, Charité - Universitätsmedizin Berlin, Berlin, 3Institut für klinische Neuroanatomie, Goethe-Universität Frankfurt am Main, Frankfurt/Main

Objective
To examine expression of the profibrotic cytokine TGF-beta1 after selective intrastromal corneal injury using a femtosecond (fs) laser.
Methods
Twelve rabbits underwent monocular intrastromal keratotomy at a preoperatively determined corneal depth of 160-200 µm using a fs laser. The fs laser-induced TGF-beta1 expression was compared to non-operated control eyes and eyes treated with photorefractive keratectomy (PRK). Follow-up examinations were performed 1, 3, 7, and 28 days after surgery. TGF-beta1 protein was identified by immunofluorescence labeling. Using laser-capture microdissection (LCM), epithelial, stromal, and endothelial cell layers were collected and changes in TGF-beta1 mRNA expression were quantified using quantitative RT-PCR.
Results
TGF-beta1 mRNA and protein expression did not significantly increase after intrastromal femtosecond laser keratotomy. In contrast, TGF-beta1 was induced in corneal epithelial and stromal cells after PRK and showed up to 23-fold higher TGF-beta1 mRNA levels compared to control corneas. The increase of TGF-beta1 mRNA levels after PRK was accompanied by increased TGF-beta1 protein production.
Conclusions
Isolated stromal injury using a fs laser does not result in an induction of the profibrotic cytokine TGF-beta1. Since TGF-beta1 has been implicated in a fibrotic response of the corneal stroma to injury, absence of TGF-beta1 induction argues for a favorable wound healing response. These findings support highly selective intrastromal procedures in refractive surgery.

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