title: Effects of a vitamin D analog, alfacalcidol, on bone and skeletal muscle in glucocorticoid-treated rats.
abstract: Glucocorticoids cause secondary osteoporosis and myopathy. The efficacy of vitamin D on osteoporotic fractures is thought to be through direct effects on bone and indirect effects on muscles that help to prevent falls. However, effects of vitamin D on muscles under glucocorticoid treatment remain unclear. Six-month-old female Wistar rats were randomized to four groups: vehicle-treated controls; a prednisolone (PSL)-administered group (PSL group); an alfacalcidol-administered group (D group); and a group administered both PSL and alfacalcidol (PSL+D group). After a 4-week treatment period, maximum contractile strength and strength decrement index (SDI), an indicator of muscle fatigue, were measured in the calf muscle by electrical stimulation of the sciatic nerve. Cross-sectional area (CSA) of muscle fibers in the tibialis anterior muscle and bone mineral density (BMD) of the femur were evaluated. The PSL group showed significantly lower muscle strength, BMD and CSA of muscle fibers, and significantly higher SDI compared to the other three groups (P < 0.05). No significant differences were observed in any of these parameters among control, D, and PSL+D groups. These results suggest that in glucocorticoid-treated rats, alfacalcidol preserved not only BMD, but also muscle strength and muscle volume, and prevented muscle fatigue.
authors.affiliation: Department of Orthopedic Surgery, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, Japan. miyakosh@doc.med.akita-u.ac.jp
authors.forename: Naohisa
authors.initials: N
authors.lastname: Miyakoshi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasaki
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kasukawa
authors.forename: Keiji
authors.initials: K
authors.lastname: Kamo
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Shimada
mesh_terms: D000818:Animals; D015519:Bone Density; D050071:Bone Density Conservation Agents / Q000494:pharmacology*; D001842:Bone and Bones / Q000187:drug effects*; D005260:Female; D005938:Glucocorticoids / Q000009:adverse effects*; D006887:Hydroxycholecalciferols / Q000008:administration & dosage*; D018763:Muscle Fatigue; D018485:Muscle Fibers, Skeletal / Q000187:drug effects*; D009133:Muscular Atrophy / Q000517:prevention & control; D010024:Osteoporosis / Q000473:pathology / Q000517:prevention & control; D058866:Osteoporotic Fractures / Q000188:drug therapy; D011239:Prednisolone / Q000008:administration & dosage; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D050071:Bone Density Conservation Agents; D005938:Glucocorticoids; D006887:Hydroxycholecalciferols; D011239:Prednisolone; C008088:alfacalcidol