Corticosteroid treatment of laser retinal damage affects prostaglandin E2 response

The current study investigated the effect of steroid treatment of eyes subjected to a single retinal argon laser lesion on vitreal accumulation of both prostaglandin E2 (PGE2) and protein and their relationship with the amounts of PGE2 released from the retina-choroid. Laser exposure resulted in an elevation in the amounts of PGE2 released by the retina-choroid of laser-treated eyes: there was an initial peak on day 1, followed by a higher peak on day 7 (13.0 +/- 3.9 ng/mg protein and 32.9 +/- 4.9 ng/mg protein, respectively) after which levels progressively declined. Steroid treatment prevented the initial peak, but did not prevent the enhanced PGE2 amounts released during the second week. Thus, on day 7 the amounts released were lower by 32% than in the untreated group (21.0 +/- 8.6 ng/mg protein vs 32.9 +/- 4.9 ng/mg protein, P = 0.000); by day 14, however, peak values in the treated group were higher than in the untreated group (32.2 +/- 12.4 ng/mg protein and 10.6 +/- 4.5 ng/mg protein, respectively). In steroid-treated eyes, vitreal PGE2 concentration remained unchanged from baseline over a 2-week follow-up, whereas in the untreated laser group, levels peaked on day 7 to 10.7 +/- 3.6 ng/ml, exceeding baseline levels of 5.8 +/- 1.7 ng/ml (P = 0.0002). Laser exposure was also associated with a biphasic elevation in vitreal protein concentrations on days 3 and 14 (0.68 +/- 0.16 mg/ml and 0.79 +/- 0.13 mg/ml, respectively); these were significantly higher than the baseline value of 0.43 +/- 0.12 mg/ml (P = 0.03 and P = 0.004, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)