title: Influence of icing on muscle regeneration after crush injury to skeletal muscles in rats.
abstract: The influence of icing on muscle regeneration after crush injury was examined in the rat extensor digitorum longus. After the injury, animals were randomly divided into nonicing and icing groups. In the latter, ice packs were applied for 20 min. Due to the icing, degeneration of the necrotic muscle fibers and differentiation of satellite cells at early stages of regeneration were retarded by ∼1 day. In the icing group, the ratio of regenerating fibers showing central nucleus at 14 days after the injury was higher, and cross-sectional area of the muscle fibers at 28 days was evidently smaller than in the nonicing group. Besides, the ratio of collagen fibers area at 14 and 28 days after the injury in the icing group was higher than in the nonicing group. These findings suggest that icing applied soon after the injury not only considerably retarded muscle regeneration but also induced impairment of muscle regeneration along with excessive collagen deposition. Macrophages were immunohistochemically demonstrated at the injury site during degeneration and early stages of regeneration. Due to icing, chronological changes in the number of macrophages and immunohistochemical expression of transforming growth factor (TGF)-β1 and IGF-I were also retarded by 1 to 2 days. Since it has been said that macrophages play important roles not only for degeneration, but also for muscle regeneration, the influence of icing on macrophage activities might be closely related to a delay in muscle regeneration, impairment of muscle regeneration, and redundant collagen synthesis.
authors.affiliation: Department of Rehabilitation Sciences, Kobe Univ. Graduate School of Health Sciences, 7-10-2 Tomogaoka, Suma-ku, Kobe, 654-0142 Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Takagi
authors.forename: Naoto
authors.initials: N
authors.lastname: Fujita
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Arakawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Kawada
authors.forename: Naokata
authors.initials: N
authors.lastname: Ishii
authors.forename: Akinori
authors.initials: A
authors.lastname: Miki
mesh_terms: D000818:Animals; D003444:Crush Syndrome / Q000503:physiopathology* / Q000628:therapy*; D007036:Hypothermia, Induced / Q000379:methods*; D007053:Ice; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries* / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration / Q000502:physiology*; D017695:Soft Tissue Injuries / Q000503:physiopathology / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D007053:Ice