Effects of positive pressure in odontogenic keratocysts

Intracystic fluid pressure is thought to be involved in odontogenic cyst growth. In this study, we investigated the effects of positive pressure on the expression of interleukin-1 alpha (IL-1 alpha), matrix metalloproteinases ( MMPs), and prostaglandin E-2(PGE(2)) in odontogenic keratocysts to determine whether this pressure stimulates inflammatory cytokine production and signaling of osteoclastogenic events. Positive pressure enhanced the expression of IL-1 alpha mRNA and protein in odontogenic keratocyst epithelial cells, and increased the secretion of MMP-1, MMP-2, MMP-3, and PGE2 in a co-culture of odontogenic keratocyst fibroblasts and the epithelial cells. The pressure-induced secretions were inhibited by an interleukin-1 receptor antagonist. Recombinant human interleukin-1 alpha ( rhIL-1 alpha) increased the secretion of MMP-1, MMP-2, MMP-3, and PGE(2) in the fibroblasts. Furthermore, in the fibroblasts, rhIL-1 alpha enhanced the expression of macrophage colony-stimulating factor (M-CSF) mRNA, and rhIL-1 alpha- induced PGE(2) increased the expression of nuclear factor kappa B ligand (RANKL) mRNA. Thus, positive pressure may play a crucial role in odontogenic keratocyst growth via stimulating the expression of IL-1 alpha in epithelial cells.