Abstract
P 071
Expression of matrix metalloproteinase (MMP) 2 and 9 and vascular endothelial growth factor (VEGF) by cultivated porcine RPE-choroid explants after selective retina therapy (SRT).
Felix Treumer1, Yoko Miura1, Alexa Klettner1, Ralf Brinkmann2, Reginald Birngruber2, Johann Roider1, Jost Hillenkamp1
1Klinik für Ophthalmologie, Campus Kiel, Universitätsklinikum Schleswig-Holstein, Kiel, 2Medizinisches Laserzentrum Lübeck, Lübeck
Objective
To investigate biochemical responses of porcine RPE after SRT for irradiations below and above LD50 threshold radiant exposure for RPE cell death.
Methods
Fresh porcine RPE-Bruch-choroid explants maintained in culture medium were irradiated with a pulsed Nd:YLF laser (wave length 527 nm, pulse duration 1.7 µs, repetition rate 100 Hz, spot size 200 µm) with energies ranged from of 140 to 180 mJ/cm2 and cultured in a static culture medium for 3 days. Threshold radiant exposure for cell damage was determined by calcein-AM cell viability test. Following laser irradiation, media samples were obtained every 24 hours. For quantification of matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor (VEGF) gelatine gel zymography and enzyme-linked immunosorbent assay (ELISA) were performed.
Results
The threshold radiant exposure for cell death was determined to be between 150 and 160 (±10) mJ/cm2. 24 hours after laser irradiation with energies ≥ 140 mJ/cm2, levels of MMP-2 increased 1.6 to 2.0-fold compared to the control non-treated samples. No significant increase of the MMP-9 and VEGF level was detected.
Conclusions
MMP-2 most likely contributes to the RPE healing response after SRT. Even close below the threshold radiant exposure, significant levels of MMP-2 are released, while levels of MMP-9 and VEGF seem to remain unchanged.
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