The correlation between excessive vitreal protein levels, prostaglandin E2 levels, and the blood retinal barrier

Changes in vitreal protein and prostaglandin E2 (PGE2) concentrations, as well as chorioretinal in vitro PGE2 production, were studied in rabbit eyes following Neodymium (Nd):YAG laser retinal exposure. Laser exposure was associated with an enhanced vitreal PGE2 concentration throughout a two-week observation period, with highest levels on days 1 and 7 after exposure (a 5.3 and 4.7 increase above baseline, respectively). A transitory 50% elevation above baseline in vitreal protein levels was observed in the laser-exposed eyes during the second week after exposure. Laser exposure was also associated with an enhancement in the in vitro chorioretinal PGE2 production, which varied throughout the observation period, and was more pronounced during the first week after exposure, when levels were four times higher than baseline. Initially PGE2 vitreal levels were closely related to excessive in vitro production. However, during the second week after exposure, evidence of such correlation was lacking, but PGE2 vitreal levels coincided with a small increase in vitreal protein levels. It is suggested that disruption of the blood retinal barrier by the long-term exposure to mildly elevated vitreal PGE2 levels was accountable for protein leakage, which might have affected PGE2 removal mechanisms.