Functional overloading facilitates the regeneration of injured soleus muscles in mice.
The effect of functional overloading on the regenerating process of injured skeletal muscle was investigated in 10-week-old male mice (C57BL/6J). Functional overloading on soleus of both hindlimbs was performed by cutting the distal tendons of plantaris and gastrocnemius muscles for 2 weeks before cardiotoxin (CTX) injection as the preconditioning and also during 10 weeks of recovery. To activate the necrosis-regeneration cycle, 0.1 ml of 10-microM CTX was injected into soleus muscle. The mean values of absolute muscle weight and the percentage of Pax7-positive nuclei in soleus were increased by the preconditioning. These values, as well as total muscle protein content, in the group with CTX injection plus overloading were larger than in the group with CTX injection alone. Fibers with central nucleus were noted in the group with CTX injection with or without overloading. The rate of disappearance of fibers having central nucleus during recovery was stimulated by overloading. Histological analyses revealed that the regeneration of injured soleus muscle with overloading proceeded more rapidly than the muscle without overloading. These results, in combination with previous lines of evidence, strongly suggest that functional overloading may facilitate the regeneration of injured skeletal muscles.
Department of Physiology, St. Marianna University School of Medicine, Kawasaki, 216-8511 Japan.
Shigeta
S
Morioka
Katsumasa
K
Goto
Atsushi
A
Kojima
Toshihito
T
Naito
Yusuke
Y
Matsuba
Tatsuo
T
Akema
Hiroto
H
Fujiya
Takao
T
Sugiura
Yoshinobu
Y
Ohira
Moroe
M
Beppu
Haruhito
H
Aoki
Toshitada
T
Yoshioka
D000818:Animals; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D004195:Disease Models, Animal; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D009135:Muscular Diseases / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D009336:Necrosis; D009929:Organ Size; D051763:PAX7 Transcription Factor / Q000378:metabolism; D012038:Regeneration; D013314:Stress, Mechanical; D013710:Tendons / Q000601:surgery; D013997:Time Factors; D014118:Toxins, Biological
D009124:Muscle Proteins; D051763:PAX7 Transcription Factor; C497322:Pax7 protein, mouse; D014118:Toxins, Biological