The effects of interleukin-1 and prostaglandin E2 on accumulation of collagen and steady-state levels of pro alpha 1(I) collagen messenger RNA in experimental granulation tissue in rats.

Abstract

The effects of human interleukin 1 beta (IL-1 beta) and prostaglandin E2 (PGE2) on experimental granulation tissue in rats and on granulation tissue cells in culture were studied. IL-1 beta and PGE2 were injected into subcutaneously implanted sponges during the first 3 days after implantation. The rate of collagen synthesis in fibroblasts was measured as synthesis of protein-bound 3H-hydroxyproline. The steady-state levels of pro alpha 1(I) and pro alpha 1(III) collagen chain mRNAs were estimated by Northern transfer analyses. By 7 days postoperatively IL-1 beta had decreased the hydroxyproline content of granulation tissue. PGE2 decreased non-significantly the amounts of hydroxyproline, but the steady-state levels of pro alpha 1(I) and pro alpha 1(III) collagen chain mRNAs were slightly elevated. In IL-1 beta-treated fibroblast cultures collagen production decreased by 15% and following PGE2 treatment by 34% compared with the controls. The latter effect could be abolished by indomethacin. Indomethacin alone stimulated collagen production by 40%. In vivo IL-1 decreases the formation of normal granulation tissue. This effect may be partly due to stimulation of secretion of PGE2.