Journal of Dental Research, Vol 69, 1456-1462, Copyright © 1990 by International & American Associations for Dental Research Online Journals
Interactive effects between cytokines on PGE production by human periodontal ligament fibroblasts in vitro
S. Saito, P. Ngan, M. Saito, R. Lanese, J. Shanfeld and Z. Davidovitch
Department of Orthodontics, Showa University, Tokyo, Japan.
Mononuclear cell production of cytokines that stimulate fibroblast
production of prostaglandin E (PGE) is an important mechanism by which
mononuclear cells regulate fibroblast function. The objective of this
investigation was to determine the effects of the cytokines interleukin 1
beta (IL-1 beta), interleukin 1 alpha (IL-1 alpha), tumor necrosis factor
alpha (TNF-alpha), and interferon gamma (IFN-gamma), alone or in paired
combinations, on PGE production by near-confluent human periodontal
ligament (PDL) fibroblasts in vitro. Premolars extracted in the course of
orthodontic treatment were used for this study. Fibroblast cultures, free
of epithelial cells, were obtained after the fourth subculture by the use
of accurately-timed trypsin treatment. Cells in the fourth to sixth
passage, incubated in DMEM supplemented with 10% equine serum, were used
for these experiments. Cells (1 x 10(5)) were seeded in 12- x -75-mm tissue
culture tubes and incubated with various doses of IL-1 beta, IL-1 alpha,
TNF-alpha, and IFN-gamma, alone or in specific combinations, for 15 min,
two, 12, 24, and 72 h. PGE concentrations in the media were measured by
radio-immunoassay. The results showed that human PDL fibroblasts responded
to the administration of cytokines by an elevation in the synthesis of PGE
in a dose- and time-related fashion. The increase in PGE production was
inhibited by the addition of indomethacin. The interactions between these
cytokines varied in degree, depending on the particular combinations of
cytokines. In addition, the administration of cytokine combinations was
found to be additive, synergistic, subtractive, or suppressive on the
production of PGE by PDL fibroblasts, depending on the duration of
incubation. These experiments demonstrate the importance of the
consideration of the interplay between cytokines produced by mononuclear
cells on the mechanisms that regulate the functions of PDL fibroblasts.
