Prostaglandins and Other Lipid Mediators Effects of prostaglandin E 2 on bone in mice in vivo

We have examined the effects of varying doses, schedules and routes of administration of prostaglandin E2 (PGE2) on bone in mice. Male C57BL/6 mice treated with a high dose of PGE2 (6 mg/kg/d) showed decreased trabecular bone volume (BV/TV) by 14 d, indicating increased bone resorption. However, there was also stimulation of bone formation at 14 d after 3 d treatment with PGE2, since mineral apposition rate (MAR) and bone formation rate (BFR/BS) were increased. In CD-1 male and female mice, PGE2 (3 mg/kg, 2/wk for 4 wk) increased MAR by 50% and BFR/BS by 100%, but there was no significant change in BV/TV. Tibial mRNA showed an increase in BMP-2 and RUNX-2 expression with PGE2. Additional experiments using a higher dose or longer exposure did not increase bone mass. We conclude that exposure to high Gene expression Bone histomorphometry Bone formation B A doses of PGE2 in mice may be anabolic but is balanced by catabolic effects. Studies of PGE2 in combination with an inhibitor of resorption could lead to development of a true anabolic model and permit assessment E2 rec