title: Effect of anti-osteoporotic agents on the prevention of bone loss in unloaded bone.
abstract: Pharmaceutical countermeasures to treat disuse osteoporosis are rarely studied. Pharmaceutical studies for the treatment and prevention of osteoporosis depend on the ovariectomized rat model, which is a suitable model for the disease in women. Disuse osteoporosis affects men and women, but there is lack of awareness and relevant pharmaceutical studies for this condition. The objectives of this study were to verify the validity of an unusual tail-suspension rat model in the induction of disuse osteoporosis and subsequent pharmaceutical treatments. This model was created by unloading the hind limbs of the rats in order to create a state of weightlessness in their hindlimb bones. Validation of the model was performed with non-suspended rats. This study included five groups of suspended rats fed with different agents, such as distilled water (control), high-, medium- and low-dose raloxifene and a bisphosphonate (alendronate). The experiment lasted for 28 days. Comparisons were made between the suspended control and treatment groups. Ovariectomized and sham‑operated rats were also included as a reference for bone changes during osteoporosis. Changes in bone mineral density (BMD) at the distal femur and proximal tibia, microarchitecture at the distal femur and biomechanical strength at the diaphyseal femur were studied. Reduction of BMD and deterioration of trabeculae were similar between the suspended control and ovariectomized rats. Loss of BMD induced by tail suspension was reduced most effectively by medium-dose raloxifene. Deterioration of trabecular microarchitecture was also prevented by raloxifene. The tail-suspension rat model is suitable for the study of disuse osteoporosis under the effects of various therapeutic agents. The preventive effects of raloxifene against bone loss under disuse conditions have been demonstrated using this model.
authors: Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, P.R. China.
authors: Wing Sum
authors: WS
authors: Siu
authors: Chun Hay
authors: CH
authors: Ko
authors: Leung Kim
authors: LK
authors: Hung
authors: Ching Po
authors: CP
authors: Lau
authors: Clara Bik San
authors: CB
authors: Lau
authors: Kwok Pui
authors: KP
authors: Fung
authors: Ping Chung
authors: PC
authors: Leung
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D005260:Female; D005269:Femur / Q000187:drug effects / Q000473:pathology; D019417:Hindlimb Suspension; D008297:Male; D010024:Osteoporosis / Q000517:prevention & control*; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013977:Tibia / Q000187:drug effects / Q000473:pathology; D014893:Weightlessness; D018474:Weightlessness Simulation
chemical_list: D050071:Bone Density Conservation Agents; D020849:Raloxifene Hydrochloride