Modulation of satellite cells in rat facial muscle following denervation and delayed reinnervation.
CONCLUSIONS
Long-term denervation-induced satellite cells (SCs) deficiency impairs facial muscle regenerative capacity. Delayed reinnervation can reactivate residual SCs to engage in muscle regeneration. However, the underlying mechanism remains to be elucidated.


OBJECTIVE
To evaluate the effects of denervation and delayed reinnervation on SCs in facial muscle.


METHODS
This was a prospective, randomized, controlled study in the rat facial nerve ligation and delayed decompression model. Animals were divided into denervation, 8-week-delay, and 16-week-delay reinnervation groups. Sham-operated animals served as a control group. Specific markers were used to investigate the differences in SC status, including quiescent (Pax7) and activated (myoD and myogenin) SCs and regenerative myofibers (embryonic myosin heavy chain, eMyHC). Quantitative assessment was performed by real-time PCR and Western blotting.


RESULTS
Activated SCs were detected 2-4 weeks after denervation and maintained for 4-8 weeks, accompanied by regenerating myofibers, whereas no SCs were detected beyond 20 weeks post-denervation. The myoD and myogenin up-regulation peaked 6-8 weeks after denervation and declined gradually to normal baseline 12 weeks after denervation. The 8-week-delay reinnervation group showed more activated SCs and regenerating myofibers than the 16-week-delay group, as well as greater up-regulation of myoD and myogenin (p < 0.05), suggesting reactivation of SCs for repair of adjacent fibers.
Chen
Donghui
D
Department of Otorhinolaryngology-Head & Neck Surgery, Changhai Hospital, Second Military Medical University, Shanghai, China.
Chen
Shicai
S
Wang
Wei
W
Liu
Fei
F
Zhang
Chuansen
C
Zheng
Hongliang
H
D000818:Animals; D015153:Blotting, Western; D005152:Facial Muscles / Q000294:innervation* / Q000473:pathology; D005158:Facial Paralysis / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008866:Microsurgery; D009000:Monocytes / Q000473:pathology; D009121:Muscle Denervation; D017570:MyoD Protein / Q000235:genetics; D018008:Myogenin / Q000235:genetics; D009416:Nerve Regeneration / Q000235:genetics / Q000502:physiology*; D051761:Paired Box Transcription Factors / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D032496:Satellite Cells, Skeletal Muscle / Q000473:pathology / Q000502:physiology*; D015854:Up-Regulation / Q000235:genetics
D017570:MyoD Protein; C503803:Myog protein, rat; D018008:Myogenin; C530821:PAX7 protein, rat; D051761:Paired Box Transcription Factors