| Research Abstract |
Intracystic fluid pressure has been thought to play a crucial role in the growth of odontogenic jaw cysts. We investigated the relationship between intracystic fluid pressure and cyst size in odontogenic keratocysts, dentigerous cysts, and radicular cysts. Intracystic fluid pressure was negatively correlated with the radiolucent area in odontogenic keratocysts (g=-0.76,n=9,p=0.018) as well as in dentigerous cysts (g=0.54,n=16,p=0.031) and radicular cysts (g=-0.69,n=10,p=0.025). The radiolucent area of the cyst on a panoramic radiogram was linearly related to the volume of the cyst cavity, and the correlation coefficient (g) was 0.70(n=25,p<0.001). Thus, intracystic fluid pressure may be negatively related to the cyst size in odontogenic keratocysts, dentigerous cysts, and radicular cysts. Then, we investigated the effects of positive pressure on the expression of interleukin-1α(IL-1α), matrix metalloproteinases(MMPs), and prostaglandin E_2(PGE_2) in odontogenic keratocysts. Positive pressure enhanced the expression of IL-1α mRNA and protein in odontogenic keratocyst epithelial cells, and increased the secretion of MMP-1,MMP-2,MMP-3,and PGE_2 in a co-culture of odontogenic keratocyst fibroblasts and the epithelial cells. The pressure-induced secretions were inhibited by the interleukin-1 receptor antagonist. Recombinant human interleukin-1α(rhIL-1α) increased the secretion of MMP-1,MMP-2,MMP-3,and PGE_2 in the fibroblasts. Furthermore, in the fibroblasts, rhIL-1α enhanced the expression of macrophage colony-stimulating factor(M-CSF) mRNA, and rhIL-1α-induced PGE_2 increased the expression of nuclear factor kB ligand(RANKL) mRNA. Thus, positive pressure may play a crucial role in odontogenic keratocyst growth via stimulating the expression of IL-1α in epithelial cells.
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