Effects of enamel matrix derivative on periodontal wound healing in an inflammatory environment in vitro

Abstract

This in vitro study was established to investigate whether the regenerative capacity of periodontal ligament (PDL) cells in the presence of enamel matrix derivative (EMD) is modulated by inflammation. PDL cells were grown in the presence or absence of EMD under normal and inflammatory conditions for up to 14 days. In order to mimic an inflammatory environment, cells were incubated with interleukin (IL)-1β. Cells were also exposed to transforming growth factor (TGF)-β1 and insulin-like growth factor (IGF)-1 under both conditions. For analysis of wound healing, an in vitro wound fill assay was used. The synthesis of growth factors, markers of proliferation, and osteogenic differentiation, as well as collagen was studied by real-time polymerase chain reaction, enzyme-linked immunoassay, and immunoblotting. Mineralization was assessed by alizarine red S and von Kossa staining. EMD stimulated significantly the in vitro wound fill rate, cell proliferation and adhesion, synthesis of growth factors, and collagen, as well as mineralization. In the presence of IL-1β, these EMD effects were significantly reduced. IL-1β also inhibited significantly the wound fill rate induced by TGF-β1 and IGF-1. Critical PDL cell functions that are associated with periodontal regeneration are reduced in an inflammatory environment.