Radiation retards muscle differentiation but does not affect osteoblastic differentiation induced by bone morphogenetic protein-2 in C2C12 myoblasts.
OBJECTIVE
Effects of radiation on the differentiation of C2C12 myoblasts were studied using cell cultures in which the cells differentiated into either muscle cells or osteoblasts.


METHODS
A mouse skeletal myoblast cell line, C2C12, was cultured and irradiated at confluence. Muscle differentiation was estimated by counting the number of myosin heavy chain (MHC)-positive multinucleated myotubes. Osteoblast differentiation was analysed by measuring alkaline phosphatase (ALP) activity and osteocalcin production in C2C12 cells treated with recombinant human bone morphogenetic protein-2 (rhBMP-2).


RESULTS
Myotube formation in C2C12 cells was inhibited by 2 and 4 Gy irradiation, but recovered to non-irradiated control levels following further culture. In irradiated cultures, the number of MHC-positive mononucleated cells increased significantly. Irradiation did not, however, alter the induction of osteoblastic phenotypes induced by rhBMP-2 in C2C12. Irradiation also did not affect the expression of MyoD mRNA and myogenin mRNA in myogenic differentiation and induction of osteocalcin mRNA in osteoblastic differentiation.


CONCLUSIONS
During differentiation of C2C12 cells, myotube formation was delayed after irradiation, while induction of osteoblasts with BMP-2 was unaffected.
Ikeda
S
S
Department of Radiology, Showa University School of Dentistry, Tokyo, Japan.
Hachisu
R
R
Yamaguchi
A
A
Gao
Y H
YH
Okano
T
T
D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects*; D002460:Cell Line; D006801:Humans; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects*; D018008:Myogenin / Q000096:biosynthesis / Q000235:genetics; D018995:Myosin Heavy Chains / Q000096:biosynthesis; D009218:Myosins / Q000096:biosynthesis / Q000235:genetics; D010006:Osteoblasts / Q000166:cytology / Q000201:enzymology*; D015675:Osteocalcin / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D016212:Transforming Growth Factor beta
C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; C503799:MYOG protein, human; C503801:Myog protein, mouse; D018008:Myogenin; D012333:RNA, Messenger; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D015675:Osteocalcin; D000469:Alkaline Phosphatase; D018995:Myosin Heavy Chains; D009218:Myosins