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Intrastromal keratotomy with femtosecond laser avoids profibrotic TGF-beta1 induction
Christian Meltendorf1, Guido J Burbach, Christian Ohrloff
1Department of Ophthalmology, Goethe-University Clinic, Frankfurt am Main, Germany. christian.meltendorf@medizin.uni-halle.de
Purpose:
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.
Insights
Selective intrastromal corneal injury using a femtosecond laser does not increase TGF-beta1 expression. This suggests a favorable wound-healing response for refractive surgery, unlike photorefractive keratectomy (PRK).
Area of Science:
- Ophthalmology
- Corneal Surgery
- Laser Technology
Background:
- The profibrotic cytokine TGF-beta1 plays a role in corneal wound healing and fibrosis.
- Understanding TGF-beta1 expression after different corneal surgical procedures is crucial for assessing wound-healing responses.
Purpose of the Study:
- To investigate the expression of TGF-beta1 following intrastromal corneal injury induced by a femtosecond laser.
- To compare TGF-beta1 expression after femtosecond laser intrastromal keratotomy with that after photorefractive keratectomy (PRK).
Main Methods:
- Rabbits underwent femtosecond laser intrastromal keratotomy (ISK) at a depth of 160-200 µm.
- TGF-beta1 protein and mRNA levels were assessed using immunofluorescence and quantitative RT-PCR at 1, 3, 7, and 28 days post-surgery.
- Comparison was made between ISK, PRK, and control eyes.
Main Results:
- Intrastromal femtosecond laser keratotomy did not significantly alter TGF-beta1 mRNA or protein expression.
- Photorefractive keratectomy (PRK) induced a significant increase in TGF-beta1 in corneal epithelial and stromal cells, with up to 23-fold higher mRNA levels compared to controls.
- Increased TGF-beta1 mRNA levels after PRK correlated with elevated protein production.
Conclusions:
- Isolated intrastromal corneal injury with a femtosecond laser does not induce the profibrotic cytokine TGF-beta1.
- The absence of TGF-beta1 induction suggests a favorable wound-healing profile for femtosecond laser-based intrastromal procedures.
- These findings support the use of highly selective intrastromal procedures in refractive surgery.
