1. Differential stimulation of prostaglandin G/H synthase-2 in osteocytes and other osteogenic cells by pulsating fluid flow.
- Author
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Westbroek I, Ajubi NE, Alblas MJ, Semeins CM, Klein-Nulend J, Burger EH, and Nijweide PJ
- Subjects
- Animals, Cells, Cultured, Chick Embryo, Cyclooxygenase 2, Enzyme Activation, Enzyme Induction, Fibroblasts metabolism, Isoenzymes genetics, Osteoblasts metabolism, Prostaglandin-Endoperoxide Synthases genetics, RNA, Messenger metabolism, Isoenzymes metabolism, Osteocytes enzymology, Prostaglandin-Endoperoxide Synthases metabolism, Pulsatile Flow physiology
- Abstract
Mechanical stress produces flow of fluid in the osteocytic lacunar-canalicular network, which is likely the physiological signal for the adaptive response of bone. We compared the induction of prostaglandin G/H synthase-2 (PGHS-2) by pulsating fluid flow (PFF) and serum in osteocytes, osteoblasts, and periosteal fibroblasts, isolated from 18-day-old fetal chicken calvariae. A serum-deprived mixed population of primarily osteocytes and osteoblasts responded to serum with a two- to threefold induction of PGHS-2 mRNA. Serum stimulated PGHS-2-derived PGE(2) release from osteoblasts and osteocytes but not from periosteal fibroblasts as NS-398, a PGHS-2 blocker, inhibited PGE(2) release from osteocytes and osteoblasts with 65%, but not that from periosteal fibroblasts. On the other hand PFF (0.7 Pa, 5 Hz) stimulated (3 fold) PGHS-2 mRNA only in OCY. The related PGE(2) response could be completely inhibited by NS-398. We conclude that osteocytes have a higher intrinsic sensitivity for loading-derived fluid flow than osteoblasts or periosteal fibroblasts., (Copyright 2000 Academic Press.)
- Published
- 2000
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