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F. Treumer, Y. Miura, A. Klettner, R. Brinkmann, R. Birngruber, J. Roider, J. Hillenkamp; The Effect of Selective Retina Therapy (SRT) on the Expression of Matrixmetalloproteinase-2 (MMP-2) and Vascular Endothelial Growth Factor (VEGF) by Cultivated Porcine RPE-choroid Explants. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3411.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate wound healing and biochemical responses of porcine RPE after SRT for irradiations below and above ED50 threshold radiant exposure for RPE cell death.
Fresh porcine RPE-Bruch-Choroid explants maintained in a 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 200µm) with energies ranged from 100 to 200 mJ/cm2 (n=4-6 for each energy) and cultured in a static culture medium for 4 days. Threshold radiant exposure for cell damage was determined by Calcein-AM cell viability test. RPE wound healing was assessed by actin staining with FITC-phalloidin. Following laser irradiation, media samples were obtained every 24 hours for quantification of matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) by enzyme-linked immunosorbent assay (ELISA).
The threshold radiant exposure for cell viability was determined to be between 150 and 160 mJ/cm2. Complete wound closure occurred within 4 days after laser irradiation. Twenty four hours after laser irradiation with energies ≥ 140 mJ/cm2, levels of MMP-2 increased 1.7 to 2.2-fold compared to the control non-treated samples. After 3-4 days, the level of MMP-2 had decreased to the level of the control. No significant increase of the VEGF level was detected.
MMP-2 most likely contributes strongly to the RPE healing response after SRT. Even close below the threshold radiant exposure, significant levels of MMP-2 are released, while levels of VEGF seem to remain unchanged.
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