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.
Turner
C H
CH
Department of Ortopaedic Surgery, Indiana University Medical Center, Indianapolis 46202.
Sato
M
M
Bryant
H U
HU
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