The expression kinetics of myogenin in facial muscle denervation.
OBJECTIVE
To study the expression kinetics of myogenin in long-term denervated facial muscle and to explore the possibility of gene therapy for facial muscle paralysis with myogenin gene.


METHODS
In 48 New Zealand rabbits, buccal muscle paralysis of one side was produced by excision of 1 cm segment buccal branch of the facial nerve. The opposite side served as controls. The animals were sacrificed and the buccal muscles of both sides were removed for examination at 1 day, 3 days, 1 week, 2 weeks, 1 month, 2 months, 4 months, and 6 months after the initial operation. The myogenin expression in denervated and innervated buccal muscles was analyzed by Western blot. Satellite cell proliferation was detected with proliferating cell nuclear antigen (PCNA) analysis. Muscle nucleic acid concentration was determined through acridine orange (AO) staining method.


RESULTS
Myogenin expression increased to the highest level at 3 days after denervation, thereafter it gradually decreased. The Western blotting signal for myogenin intensified again after 1 month and at 4 months. In contrast, the highest expression of the controls (innervated muscles) were observed at 1 month. These changes in myogenin expression in denervated buccal muscles were consistent with the change in satellite cell proliferation and in muscle nucleic acid concentration.


CONCLUSIONS
Myogenin protein expression in longterm facial muscle denervation is closely associated with satellite cell regeneration. Myogenin may promote satellite cell differentiation, and therefore may improve the treatment of facial paralysis.
Xiao
R
R
Department of Oral and Maxillofacial Surgery, School of Stomatology, Beijing Medical University (BMU), 38 Bai Shi Qiao Road, Haidian District, Beijing, 100081, P. R. China.
Yu
G
G
Jia
H
H
Cai
Z
Z
D000165:Acridine Orange; D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation; D002455:Cell Division; D004247:DNA / Q000032:analysis; D005152:Facial Muscles / Q000294:innervation* / Q000473:pathology; D005154:Facial Nerve / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D005456:Fluorescent Dyes; D005500:Follow-Up Studies; D005786:Gene Expression Regulation; D008297:Male; D018613:Microscopy, Confocal; D009121:Muscle Denervation; D018008:Myogenin / Q000235:genetics* / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D012313:RNA / Q000032:analysis; D011817:Rabbits
D005456:Fluorescent Dyes; D018008:Myogenin; D018809:Proliferating Cell Nuclear Antigen; D012313:RNA; D004247:DNA; D000165:Acridine Orange