INTERLEUKIN-1 IN EXPERIMENTAL PROLIFERATIVE VITREORETINOPATHY

Since proliferative vitreoretinopathy (PVR) is associated with an infl ammatory reaction and interleukin-1 (IL-1) initiates a cascade of infl ammatory mediators, we determined the intravitreal levels of IL-1 in e xperimental PVR. In the blood-trauma model of PVR in rabbits, we measu red the intravitreal levels of IL-1 alpha and IL-1 beta using a radioi mmunoassay and performed immunohistochemical staining of cells from th e vitreous. We found that on day 1 polymorphonuclear and from day 2 on mononuclear inflammatory cells predominated in the vitreous. IL-1 alp ha- and IL-1 beta-positive cells with a large cytoplasm were observed on days 4 and 8. However, the IL-1 alpha and IL-1 beta concentrations in the vitreous did not exceed the radioimmunoassay sensitivity limit 8 h, 1, 2, 4 and 8 days after trauma, while in 2 control rabbits injec ted with additional endotoxins we found 5.6 and 8 ng/ml IL-1 beta. We conclude that despite IL-1-positive cells, presumably macrophages, PVR is not associated with high levels of IL-1. No conclusions concerning the low levels of IL-1 alpha and IL-beta can be drawn due to the perf ormance of the RIA.