title: Ultrastructural changes in human masseter muscles after botulinum neurotoxin a injection.
abstract: BACKGROUND
  Botulinum neurotoxin A (BoNTA) has long been used as a therapeutic agent and has been widely accepted as a cosmetic agent in recent years. It can inhibit function and induce structural changes in skeletal muscle.
  
  
  METHODS
  Specimens of fresh dissected human masseter muscle were used to observe the ultrastructural changes that occurred at 6 and 12 months following BoNTA injection.
  
  
  RESULTS
  The findings observed were muscle fiber distortion, sarcomere shortening, mitochondrial vacuolar degeneration, glycogen accumulation, and H and M band disruption in the triad of tubules. At 12 months after injection, there was still evidence of degenerative changes in muscle ultrastructure, whereas most organelles exhibited a normal structure.
  
  
  CONCLUSIONS
  Profound ultrastructural and organelle disfiguring changes were observed after BoNTA injection into human masseter muscle. Most changes were transient, however, and were resolved by 12 months after injection. Muscle Nerve 57: 96-99, 2018.
authors.affiliation: Plastic Surgery Hospital of Weifang Medical University, 288 Shenglidongjie Kuiwen Weifang, Shandong, People's Republic of China, 261042.
authors.forename: Fushun
authors.initials: F
authors.lastname: Ma
authors.affiliation: Plastic Surgery Hospital of Weifang Medical University, 288 Shenglidongjie Kuiwen Weifang, Shandong, People's Republic of China, 261042.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Zhai
authors.affiliation: Plastic Surgery Hospital of Weifang Medical University, 288 Shenglidongjie Kuiwen Weifang, Shandong, People's Republic of China, 261042.
authors.forename: Shunwen
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Plastic Surgery Hospital of Weifang Medical University, 288 Shenglidongjie Kuiwen Weifang, Shandong, People's Republic of China, 261042.
authors.forename: Shengjian
authors.initials: S
authors.lastname: Tang
mesh_terms: D000328:Adult; D044466:Asian People; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage / Q000494:pharmacology*; D005145:Face / Q000033:anatomy & histology; D005260:Female; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D007273:Injections, Intramuscular; D008406:Masseter Muscle / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008870:Microtubules / Q000378:metabolism / Q000473:pathology; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000648:ultrastructure; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000648:ultrastructure; D009465:Neuromuscular Agents / Q000008:administration & dosage / Q000494:pharmacology*; D012518:Sarcomeres / Q000187:drug effects / Q000648:ultrastructure; D013518:Surgery, Plastic; D055815:Young Adult
chemical_list: D009465:Neuromuscular Agents; D006003:Glycogen; D019274:Botulinum Toxins, Type A
keywords: Botulinum toxin A; electron microscope; human masseter muscle; mitochondria; sarcomere; ultrastructural changes