Interleukin-1beta-induced release of matrix proteins into culture media causes inhibition of mineralization of nodules formed by periodontal ligament cells in vitro.

摘要: The mechanism by which interleukin-1beta (IL-1) inhibits the formation of mineralized tissue nodules periodontal ligament (PDL) cells in vitro was investigated through processes morphological analysis, immunoprecipitation, and Northern blot analysis. PDL were obtained from a 2-day-old coagulum tooth socket cultured Dulbecco's Modified Eagle Medium (DMEM) containing 10% fetal bone serum (FBS) antibiotics. Confluent grown for up to 3 weeks presence ascorbic acid (AA), beta-glycerophosphate (GP), dexamethasone (Dex), or IL-1. GP AA did not differentiate, but those treated with Dex, GP, (Dex group) underwent differentiation, showing four stages (confluent, multilayer, nodule, mineralization) disparate characteristics. In contrast, IL-1, (IL-1 form multilayers failed nodules. Electron microscopy demonstrated that Dex-induced contain fibroblastic cells, numerous collagen fibrils, dense globular as well fused electron patches are associated apatite crystals. nodule-like structures IL-1 group also comprised multilayered they contained only small number no patches. Von Kossa staining confirmed Dex their scarceness group. analysis IL-1-treated however, revealed mRNAs type I (Col I), secreted protein, acidic rich cysteine (SPARC), osteopontin (OPN), alkaline phosphatase (ALP), sialoprotein (BSP), osteocalcin (OC), whose expression patterns levels comparable Immunoprecipitation OPN BSP cell/matrix layers culture media after [35S]-methionine labeling showed deposition primarily group, release into Immunogold location significant occurred Interestingly, treatment increased collagenase mRNA sevenfold, compared These data suggest IL-1-induced unmineralized results so much downregulated matrix proteins, plays crucial role mineralization process, media. Finally, synthesis upregulated may be involved this process.