title: The non-thermal effects of pulsed ultrasound irradiation on the development of disuse muscle atrophy in rat gastrocnemius muscle.
abstract: This study examined the effects of therapeutic pulsed ultrasound (US) on the development of disuse muscle atrophy in rat gastrocnemius muscle. Male Wistar rats were randomly distributed into control, immobilization (Im), sham US, and US groups. In the Im, sham US and US groups, the bilateral ankle joints of each rat were immobilized in full plantar flexion with a plaster cast for a 4-wk period. The pulsed US (frequency, 1 MHz; intensity, 1.0 W/cm(2); pulsed mode 1:4; 15 min) was irradiated to the gastrocnemius muscle in the US group over a 4-wk immobilization period. The pulsed US irradiation delivered only non-thermal effects to the muscle. In conjunction with US irradiation, 5-bromo-2'-deoxyuridine (BrdU) was injected subcutaneously to label the nuclei of proliferating satellite cells 1 h before each pulsed US irradiation. Immobilization resulted in significant decreases in the mean diameters of type I, IIA and IIB muscle fibers of the gastrocnemius muscle in the Im, sham US and US groups compared with the control group. However, the degrees of muscle fiber atrophy for all types were significantly lower in the US group compared with the Im and sham US groups. Although the number of capillaries and the concentrations of insulin-like growth factor and basic fibroblast growth factor did not change in the muscle, the number of BrdU-positive nuclei in the muscle was significantly increased by pulsed US irradiation in the US group. The results of this study suggest that pulsed US irradiation inhibits the development of disuse muscle atrophy partly via activation of satellite cells.
authors.affiliation: Department of Rehabilitation, Saiseikai Nagasaki Hospital, Nagasaki, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Matsumoto
authors.affiliation: Unit of Physical and Occupational Therapy, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan. Electronic address: nakano-j@nagasaki-u.ac.jp.
authors.forename: Jiro
authors.initials: J
authors.lastname: Nakano
authors.affiliation: Department of Rehabilitation, Saiseikai Nagasaki Hospital, Nagasaki, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Oga
authors.affiliation: Department of Rehabilitation, Nagasaki Memorial Hospital, Nagasaki, Japan; Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kataoka
authors.affiliation: Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Honda
authors.affiliation: Department of Rehabilitation, Nagasaki University Hospital, Nagasaki, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Sakamoto
authors.affiliation: Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Okita
mesh_terms: D000818:Animals; D019220:High-Energy Shock Waves / Q000627:therapeutic use; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D006979:Hyperthermia, Induced; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology* / Q000503:physiopathology* / Q000528:radiation effects; D020966:Muscular Disorders, Atrophic / Q000473:pathology* / Q000503:physiopathology / Q000517:prevention & control*; D051381:Rats; D017208:Rats, Wistar; D016896:Treatment Outcome
keywords: Capillary; Disuse muscle atrophy; Growth factor; Pulsed ultrasound; Rat; Satellite cell