Effect of rehabilitation protocols on muscle function and morphology following hindlimb disuse in weanling rats.
BACKGROUND
Primary or secondary disorders in developing skeletal muscles are prevalent in physical therapy practice. Assessment of gait functional changes and morphological aspects of hindlimb muscles of weanling rats have not been reported simultaneously in the literature. Rehabilitation by active (eccentric training) and passive (stretching) exercises after hypomobility needs to be investigated.


METHODS
After ten days of immobilisation in a plantar flexion-shortened position, animals underwent eccentric training on treadmills, intermittent (a single series of ten exercises of 30 seconds each, with a 30-s interval) or continuous stretching protocols for 40 minutes, or had free cage activity for three days. Analysis of gait variables and muscle morphology (immunohistochemical staining of soleus and plantar muscles for fibronectin and types I and III collagen and immunofluorescence staining for dystrophin, laminin, Pax-7, and CD68) were performed.


RESULTS
On the third day, the rehabilitated animals touched the ground surface with their toes, except for the group undergoing continuous stretching. The total amount of extracellular macrophages was higher in the rehabilitated animals. The number of satellite cells was not significantly different between groups.


CONCLUSIONS
Three days of active training (eccentric exercise) showed greater effectiveness compared to the other rehabilitation programs. Weanling rats seem to respond differently to external stimuli such as disuse and remobilisation.
Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil.
Renata Viana Brígido
RV
de Moura-Jucá
Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil.
Keite Leite
KL
Noguti
Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil.
Eduardo
E
Bianchi
Department of Pathology, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil.
Deise Lúcia Chesca
DL
Simões
Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, University of São Paulo, São Paulo, Brazil. acms@fmrp.usp.br.
Ana Claudia
AC
Mattiello-Sverzut
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D016189:Dystrophin / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D005684:Gait; D006614:Hindlimb / Q000503:physiopathology*; D019417:Hindlimb Suspension; D007797:Laminin / Q000378:metabolism; D009132:Muscles / Q000502:physiology* / Q000503:physiopathology; D009133:Muscular Atrophy / Q000503:physiopathology / Q000534:rehabilitation*; D009135:Muscular Diseases / Q000503:physiopathology / Q000534:rehabilitation; D051761:Paired Box Transcription Factors / Q000378:metabolism; D010805:Physical Conditioning, Animal; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D000097382:CD68 Molecule
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D003094:Collagen; D016189:Dystrophin; D005353:Fibronectins; D007797:Laminin; D051761:Paired Box Transcription Factors; C539355:CD68 protein, rat; D000097382:CD68 Molecule; C530821:PAX7 protein, rat