Interleukin-1 beta-induced expression of monocyte chemotactic protein-1 inthe rabbit retina: An in situ and immunohistochemical study

In this study, the temporal and spatial expression of the chemotactic facto r monocyte chemotactic protelin-1 (MCP-1) was examined in the rabbit retina after challenge with the proinflammatory cytokine interleukin-1 beta (IL-1 ). In these tissues, IL-1 induces an acute inflammatory response of the epi retinal vessels that peaks approximate to 24 h postintraocular injection (p i) with the cytokine. At 2 h after challenge with IL-1, MCP-1 mRNA was expr essed by perivascular microglial cells and astrocytes that form the glial l imitans. Protein analysis at 3 h pi with IL-1 confirmed these sites of MCP- 1 expression. The intensity of the mRNA and protein signals increased at 6 h and at 24 h. At these time points, MCP-1 message and protein also were de tected in infiltrating macrophages and, at the latest time point, in endoth elial cells as well. These data support the conclusion that IL-1 provides a strong stimulus for the rapid expression of MCP-1 mRNA and protein in reti nal tissues, and they further support the role of endogenous glial cells as important sources of mediators involved in the regulation of inflammation occurring within the nervous system. (C) 2000 Wiley-Liss, Inc.