Low magnitude of tensile strain inhibits IL-1 beta-dependent induction of pro-inflammatory cytokines and induces synthesis of IL-10 in human periodontal ligament cells in vitro

Applied mechanical loading induces inflammation in the periodontal ligament (PDL). However, the mechanisms involved in bone deposition at tension site s in an inflammatory environment are not clear. Here, in an in vitro model system, we show that equibiaxial tensile strain of low magnitude (TENS) pro vokes potent antiinflammatory signals in PDL cells. TENS inhibits IL-1 beta -induced synthesis of IL-1 beta, IL-6, and IL-8 by inhibiting their mRNA e xpression, and thus significantly suppresses the amplification of IL-1 beta -induced inflammatory responses in PDL cells. Additionally, as an anti-inf lammatory signal, TENS induces IL-10 synthesis in the presence and absence of IL-1 beta. These observations are the first to demonstrate that TENS ant agonizes IL-1 beta actions on PDL cells by (i) inhibiting IL-1 beta induced transcriptional regulation of proinflammatory cytokines, and (ii) inducing synthesis of IL-10, which may posttranscriptionally suppress the synthesis of proinflammatory cytokines.