Sequence of IGF-I, IGF-II, and HGF expression in regenerating skeletal muscle.
Various cytokines are thought to play a role in muscle regeneration, however, the interaction and mechanisms of action of these cytokines remains largely unknown. In this study, we investigated the role of HGF, IGF-I, and IGF-II during myogenesis using the regeneration model of skeletal muscle as well as myoblast culture. RT-PCR analysis revealed that HGF and IGF-I expressions were markedly upregulated, in regenerating muscle. In contrast, there was no significant difference in IGF-II expression between normal and regenerating muscle. Immunohistochemical analysis demonstrated that HGF was expressed mostly by myocytes during the early stages of muscle regeneration. Additionally, HGF inhibited the formation of myotubes by myoblasts, but promoted cellular proliferation. Otherwise, IGF-I and IGF-II were expressed by myocytes through the early to middle stages of muscle regeneration. The addition of HGF to myoblast growing in vitro significantly increased the number of cells. These findings indicate that these three cytokines have pleiotropic effects in regenerating skeletal muscle.
Laboratory of Functional Morphology, Division of Life Science, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, 981-8555, Sendai, Japan.
Shinichiro
S
Hayashi
Hisashi
H
Aso
Kouichi
K
Watanabe
Hidetoshi
H
Nara
Michael T
MT
Rose
Shyuichi
S
Ohwada
Takahiro
T
Yamaguchi
D000818:Animals; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D017228:Hepatocyte Growth Factor / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000502:physiology*; D032446:Myoblasts / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D012038:Regeneration; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D012333:RNA, Messenger; D011994:Recombinant Proteins; D017228:Hepatocyte Growth Factor; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II