title: Effects of voluntary resistance exercise and high-protein snack on bone mass, composition, and strength in rats given glucocorticoid injections.
abstract: We examined the effects of a voluntary resistance exercise (climbing) together with high-protein snacks (60% protein) on bone mass and strength in rats given glucocorticoid-injections (2 mg/kg/day) as a model of age-related osteopenia. Fifty-two male Sprague-Dawley rats, 8 weeks age, were assigned to exercise or sedentary groups. These groups were further divided into groups that received no snack, snack during activity or a snack during rest. All groups were meal-fed 7:30-8:30 h and 19:30-20:30 h and the snack was fed 23:30-0:30 h (active) or 11:30-12:30 h (resting). Energy and protein intake were approximately equal in all groups. The exercise groups were allowed to climb a wire-mesh tower cage (phi 20 cm x 200 cm) to drink water from a bottle set at the top. Weight gain during the 8-week experimental period was inhibited by a glucocorticoid-injection. Bone mass and strength were increased by climbing exercise with a high-protein snack, while no effect of snack nor any effect of snack timing was observed. Bone weight, calcium content and protein content were positively correlated to maximum load or structural stiffness. These results suggest that resistance exercise and high-protein supplementation may be a preventive therapy for osteoporosis associated with aging.
authors.affiliation: Faculty of Agriculture, Kagawa University, Japan. matsuo@ag.kagawa-u.ac.jp
authors.forename: Tatsuhiro
authors.initials: T
authors.lastname: Matsuo
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nozaki
authors.forename: Koji
authors.initials: K
authors.lastname: Okamura
authors.forename: Keitaro
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Doi
authors.forename: Shoich
authors.initials: S
authors.lastname: Gohtani
authors.forename: Masashige
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D001835:Body Weight; D015519:Bone Density / Q000187:drug effects / Q000502:physiology*; D002118:Calcium; D004044:Dietary Proteins / Q000494:pharmacology*; D002149:Energy Intake / Q000502:physiology; D005938:Glucocorticoids / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D010024:Osteoporosis / Q000178:diet therapy* / Q000503:physiopathology; D010805:Physical Conditioning, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004044:Dietary Proteins; D005938:Glucocorticoids; D002118:Calcium