title: Three days of intermittent stretching after muscle disuse alters the proteins involved in force transmission in muscle fibers in weanling rats.
abstract: The aim of this study was to determine the effects of intermittent passive manual stretching on various proteins involved in force transmission in skeletal muscle. Female Wistar weanling rats were randomly assigned to 5 groups: 2 control groups containing 21- and 30-day-old rats that received neither immobilization nor stretching, and 3 test groups that received 1) passive stretching over 3 days, 2) immobilization for 7 days and then passive stretching over 3 days, or 3) immobilization for 7 days. Maximal plantar flexion in the right hind limb was imposed, and the stretching protocol of 10 repetitions of 30 s stretches was applied. The soleus muscles were harvested and processed for HE and picrosirius staining; immunohistochemical analysis of collagen types I, III, IV, desmin, and vimentin; and immunofluorescence labeling of dystrophin and CD68. The numbers of desmin- and vimentin-positive cells were significantly decreased compared with those in the control following immobilization, regardless of whether stretching was applied (P<0.05). In addition, the semi-quantitative analysis showed that collagen type I was increased and type IV was decreased in the immobilized animals, regardless of whether the stretching protocol was applied. In conclusion, the largest changes in response to stretching were observed in muscles that had been previously immobilized, and the stretching protocol applied here did not mitigate the immobilization-induced muscle changes. Muscle disuse adversely affected several proteins involved in the transmission of forces between the intracellular and extracellular compartments. Thus, the 3-day rehabilitation period tested here did not provide sufficient time for the muscles to recover from the disuse maladaptations in animals undergoing postnatal development.
authors.affiliation: Programa de Pós-Graduação em Reabilitação e Desempenho Funcional, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: M C S
authors.initials: MC
authors.lastname: Gianelo
authors.affiliation: Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: J C
authors.initials: JC
authors.lastname: Polizzelo
authors.affiliation: Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: D
authors.initials: D
authors.lastname: Chesca
authors.affiliation: Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: A C
authors.initials: AC
authors.lastname: Mattiello-Sverzut
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D024042:Collagen Type I / Q000032:analysis / Q000378:metabolism; D024061:Collagen Type III / Q000032:analysis / Q000378:metabolism; D024141:Collagen Type IV / Q000032:analysis / Q000378:metabolism; D003893:Desmin / Q000032:analysis / Q000378:metabolism; D016189:Dystrophin / Q000032:analysis; D005260:Female; D005455:Fluorescent Antibody Technique; D007103:Immobilization / Q000502:physiology*; D002479:Inclusion Bodies / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D053580:Muscle Strength / Q000502:physiology*; D052580:Muscle Stretching Exercises; D011897:Random Allocation; D017208:Rats, Wistar; D013997:Time Factors; D014746:Vimentin / Q000032:analysis / Q000378:metabolism; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D024042:Collagen Type I; D024061:Collagen Type III; D024141:Collagen Type IV; D003893:Desmin; D016189:Dystrophin; D009124:Muscle Proteins; D014746:Vimentin; C067980:CD68 antigen, human; D000097382:CD68 Molecule