Immobilization increases bone prostaglandin E. Effect of acetylsalicylic acid on disuse osteoporosis studied in dogs.
The effect of acetylsalicylic acid (aspirin) on bone mass and bone prostaglandin E (PGE) in immobilization osteoporosis was studied in 12 growing dogs using a unilateral hind limb cast-fixation model. Osteoporosis was induced by fiberglass-cast immobilization of the right hind limb for 4 weeks, with the left hind limb as a control. Six dogs received buffered aspirin at 25 mg/kg body weight per os every 8 hours; 6 dogs received no treatment. All the dogs were killed after 4 weeks, and bone samples were collected. Bone mineral content of the distal tibial metaphysis was measured by single-photon absorptiometry. In vitro release of PGE from the calcaneus, tibial cortical bone, tibial cancellous bone, and ilium were measured using a specific radioimmunoassay for PGE. Compared with the controls, the casted limb of untreated dogs had half the bone mass and a twofold increase in bone PGE. Aspirin treatment was associated with a 65 percent reduction in bone PGE and a 13 percent bone mass sparing effect. These results provide indirect evidence that PGE plays a role in immobilization osteoporosis.
Waters
D J
DJ
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul.
Caywood
D D
DD
Trachte
G J
GJ
Turner
R T
RT
Hodgson
S F
SF
D015502:Absorptiometry, Photon; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D001842:Bone and Bones / Q000737:chemistry* / Q000187:drug effects; D002118:Calcium / Q000097:blood; D004285:Dogs; D005260:Female; D007103:Immobilization; D008903:Minerals / Q000032:analysis; D010024:Osteoporosis / Q000209:etiology / Q000517:prevention & control*; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D011458:Prostaglandins E / Q000032:analysis*; D013997:Time Factors
D008903:Minerals; D010281:Parathyroid Hormone; D010710:Phosphates; D011458:Prostaglandins E; D000469:Alkaline Phosphatase; D001241:Aspirin; D002118:Calcium