Abstract
Tumor necrosis factor-a (TNF-a) is one of proinflammatory cytokines produced as early inflammatory responses, and is suggested to partici-pate in the establishment of inflammatory lesions. To understand the regulatory role of TNF-a on periodontal connective tissue, we evaluated the effect of TNF-a on DNA synthesis, collagenous and non-collagenous protein synthesis, prostaglan-din E2 (PGE2) productivity, and platelet-derived growth factor (PDGF) -A chain mRNA expression in human gingival fibroblasts (HGF).
Results indicated that 1) TNF-a promoted DNA synthesis, both collagenous and non-col-lagenous protein synthesis in HGF, 2) TNF-a markedly enhanced PGE2 production in HGF, 3) inhibition of PGE2 synthesis by the addition of in-domethacin, further augmented the ability of DNA synthesis and collagenous and non-collagenous pro-tein synthesis in HGF, and 4) TNF-a enhanced the expression of PDGF-A chain mRNA in HGF.
These results suggest that TNF-a enhances the DNA synthesis and extracellular matrix protein synthesis in HGF, but endogenous PGE2 which is induced by TNF-a, partially blocks these effects. Furthermore, the enhancement of DNA synthesis in response to TNF-a could be possibly mediated by autocrine PDGF.
