Intrastromal keratotomy with femtosecond laser avoids profibrotic TGF-beta1 induction.
OBJECTIVE
To examine expression of the profibrotic cytokine TGF-beta1 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 mum with the use of a femtosecond laser. Femtosecond laser-induced TGF-beta1 expression was compared in nonoperated 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. With the use of laser-capture microdissection, epithelial, stromal, and endothelial cell layers were collected, and changes in TGF-beta1 mRNA expression were quantified with 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 with control corneas. The increase of TGF-beta1 mRNA levels after PRK was accompanied by increased TGF-beta1 protein production.


CONCLUSIONS
Isolated stromal injury with a femtosecond laser does not result in induction of the profibrotic cytokine TGF-beta1. Because 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.
Meltendorf
Christian
C
Department of Ophthalmology, Goethe-University Clinic, Frankfurt am Main, Germany. christian.meltendorf@medizin.uni-halle.de
Burbach
Guido J
GJ
Ohrloff
Christian
C
Ghebremedhin
Estifanos
E
Deller
Thomas
T
D000818:Animals; D003319:Corneal Stroma / Q000378:metabolism* / Q000601:surgery*; D004728:Endothelium, Corneal / Q000378:metabolism; D019573:Epithelium, Corneal / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D005786:Gene Expression Regulation / Q000502:physiology*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D018903:Photorefractive Keratectomy / Q000379:methods*; D012313:RNA / Q000302:isolation & purification; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; D012313:RNA