Evidence for fibroblasts as the major source of prostacyclin and prostaglandin synthesis in dental cyst in man.

Periodontal cysts synthesize large amounts of prostaglandins and collagenase which probably cause the localized bone destruction essential for intraosseous cyst growth. Fragments of cyst wall, and fibroblasts cultured from them, synthesized prostacyclin (PGI2) in addition to prostaglandin E2 (PGE2), PGF2 alpha and collagenase in vitro. Soluble products from cultures of unstimulated and phytohaemagglutinin-stimulated blood mononuclear cells enhanced the synthesis of these prostaglandins in monolayer cultures of cyst-wall fibroblasts. It is therefore proposed that cyst capsule fibroblasts are the major source of these bone-resorbing factors, acting under the stimulus of lymphocytes and monocytes in chronically inflamed cysts. Cysts which were not infiltrated by chronic inflammatory cells (follicular cysts, a keratocyst, an ameloblastoma, and an aneurysmal bone cyst) also produced prostaglandins and collagenase, indicating that the stimulatory mechanism for the production of bone-resorbing factors in these cysts may differ from that in periodontal cysts.