[Effect of Selective Retina Therapy (SRT) on the Inflammatory Microenvironment of the Subretinal Space]

To investigate the effect of Selective Retina Therapy (SRT) on inflammatory key factors such as complement factor-C3 (CC3), tumor growth factor-beta2 (TGF-β2), tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ).

Porcine RPE-Bruch's membrane-choroid explants were irradiated with two SRT laser systems, SRT_YLF and SRT_YAG (Nd : YLF laser, wave length 527 nm, pulse duration 1.7 µs and Nd : YAG laser, wave length 532 nm, pulse duration 2.4 - 3 µs). Laser irradiation was performed on a spot size of 200 × 200 µm, 30 pulses, with a repetition rate of 100 Hz, and a radiant exposure of 140 (threshold RPE death) and 180 mJ/cm² per pulse (above threshold RPE death). Explants were cultivated in modified Ussing chambers and culture viability was assessed by calcein-AM cell staining. Secretion of inflammatory factors was analyzed by ELISA. Protein expression of tissue explants was assessed by Western blot.

Regeneration of RPE was observed after 4 days. One day after SRT with 140 mJ/cm² per pulse the secretion of basal CC3 decreased in ELISA. Following 180 mJ/cm² radiant exposure, the level of IFN-γ decreased at day 4.

SRT does not induce the release of the pro-inflammatory factors analyzed in this in-vitro study.