BONE-MINERAL DENSITY AND BIOMECHANICAL PROPERTIES OF SPINE AND FEMUR OF OVARIECTOMIZED RATS TREATED WITH NAPROXEN

Prostaglandins have been reported to mediate the effects of ovariectom y on bone loss. We studied the effect of naproxen, an inhibitor of pro duction of prostaglandins, on ovariectomy-induced bone loss. One hundr ed forty female Wistar rats 4.5 months of age were divided into groups of baseline, sham operation (sham), sham treated with naproxen at 10 mg/kg per day tin food), and ovariectomy treated with naproxen or estr ogen as intramuscular injection of estradiol at 0.2 mg/kg body weight per week, They were killed. 3, 6, and 9 months postsurgery, Bone miner al density (BMD) of the lumbar spine (L1-4), femoral neck, midshaft, a nd distal metaphysis was determined using dual-energy X-ray absorptiom etry (DXA) in vitro. The compressive test of the L1 vertebral body and torsional test of the left femur were performed, The right femoral ne ck and femoral midshaft were processed undecalcified for determining c ross-sectional moments of inertia, Naproxen treatment partially preven ted ovariectomy-induced loss or less gain in BMD, in a significant man ner, in the femoral neck cortical area, and also in L1 compressive str ength and stiffness, Estrogen fully prevented these ovariectomy-induce d effects, Naproxen showed no effect on ovariectomy-induced improvemen t in femoral torsional strength and stiffness and cross-sectional mome nts of inertia, No statistically significant difference was found betw een naproxen-treated sham rats and untreated sham rats. The data sugge st that naproxen partially prevents ovariectomy-induced osteopenia, (C ) 1998 by Elsevier Science Inc. All rights reserved.