Raloxifene preserves bone strength and bone mass in ovariectomized rats.
We investigated the effects of raloxifene, a nonsteroidal benzothiophene, on bone strength in ovariectomized rats and compared them with estrogen treatment. Sixty ovariectomized Sprague-Dawley rats were divided into three groups for treatment with orally dosed raloxifene (3 mg/kg), ethynyl estradiol (EE, 0.1 mg/kg), or vehicle. A fourth group of 20 rats that underwent sham ovariectomies and received vehicle was used for comparison. Treatments began 3 days after ovariectomy and continued for 6 months. Raloxifene treatment resulted in greater bone strength in the lumbar vertebrae (P < 0.05) and femoral neck (P < 0.01) and greater bone mineral density at the proximal tibia (P < 0.001) and lumbar vertebrae (P < 0.001) when compared with vehicle-treated ovariectomized animals. The positive effects on bone biomechanical properties from raloxifene treatment were not different than those associated with EE treatment. Raloxifene did not cause a significant increase in uterine weight, whereas EE treatment resulted in uterine weight increased 4-fold over vehicle-treated ovariectomized controls. Therefore, in rats, raloxifene has beneficial effects on bone biomechanics that are equivalent to those of EE treatment without substantial effects on the uterus.
Department of Ortopaedic Surgery, Indiana University Medical Center, Indianapolis 46202.
C H
CH
Turner
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Sato
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HU
Bryant
D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000502:physiology*; D003720:Densitometry; D004967:Estrogens / Q000494:pharmacology; D004997:Ethinyl Estradiol / Q000494:pharmacology; D005260:Female; D005272:Femur Neck / Q000502:physiology; D008159:Lumbar Vertebrae / Q000502:physiology; D009929:Organ Size; D010052:Ovariectomy; D010880:Piperidines / Q000494:pharmacology*; D020849:Raloxifene Hydrochloride; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014599:Uterus / Q000033:anatomy & histology / Q000502:physiology
D004967:Estrogens; D010880:Piperidines; D004997:Ethinyl Estradiol; D020849:Raloxifene Hydrochloride