title: Tissue engineering of injectable muscle: three-dimensional myoblast-fibrin injection in the syngeneic rat animal model.
abstract: BACKGROUND
  Surgical treatment of skeletal muscle loss resulting from trauma, tumor ablation, or inborn tissue defects is hampered by the scarcity of functional substitute tissue. By using techniques of tissue engineering, reconstitution of skeletal muscle defects might become a more viable option. However, it is necessary to develop an adequate, practical method for delivering myoblasts within a three-dimensional scaffold in vivo. The aim of this study was to create and evaluate a novel method for the transfer of myoblasts with clinically approved components within a three-dimensional matrix.
  
  
  METHODS
  The authors injected expanded primary male myoblasts into muscle defects in female syngeneic rats using a two-way syringe (Duploject) within a three-dimensional fibrin matrix. Detection and evaluation were performed using Y chromosome in situ hybridization, antidesmin immunostaining, and hematoxylin and eosin staining. To identify possible differences by means of integration, the injected myoblasts were compared with 7 days of precultivated constructs.
  
  
  RESULTS
  Injected myoblasts showed increasing integration into host muscle fibers in a time-dependent manner, exclusively at the injection site. Antidesmin staining revealed a conserved myogenic phenotype of transplanted cells. The fibrin matrix resolved over a period of 12 weeks, with no indication of an inflammatory reaction. No significant difference in the number of detected Y chromosome-positive nuclei was found between the two transplantation groups.
  
  
  CONCLUSIONS
  The presented technique of myoblast-fibrin injection indicates a clinical potential for reconstruction of skeletal muscle defects in vivo using a ready-to-use device in combination with tissue-engineering methods.
authors.affiliation: Erlangen and Freiburg, Germany From the Department of Plastic and Hand Surgery, University Hospital of Erlangen, and the Department of Plastic and Hand Surgery, Tissue Engineering Laboratory, University Hospital of Freiburg.
authors.forename: Justus P
authors.initials: JP
authors.lastname: Beier
authors.forename: Jens
authors.initials: J
authors.lastname: Stern-Straeter
authors.forename: Vanni T
authors.initials: VT
authors.lastname: Foerster
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kneser
authors.forename: G Bjoern
authors.initials: GB
authors.lastname: Stark
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Bach
mesh_terms: D000818:Animals; D001704:Biopolymers; D002470:Cell Survival; D002478:Cells, Cultured / Q000637:transplantation; D003470:Culture Media; D003893:Desmin / Q000032:analysis; D004867:Equipment Design; D005260:Female; D005337:Fibrin / Q000627:therapeutic use*; D005340:Fibrinogen / Q000008:administration & dosage; D006085:Graft Survival; D017403:In Situ Hybridization; D007273:Injections, Intramuscular / Q000295:instrumentation; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries; D032446:Myoblasts / Q000637:transplantation*; D051381:Rats; D011921:Rats, Inbred WKY; D013194:Staining and Labeling; D013594:Syringes; D013917:Thrombin / Q000008:administration & dosage; D023822:Tissue Engineering / Q000379:methods; D014185:Transplantation, Isogeneic; D014947:Wounds and Injuries / Q000601:surgery; D014998:Y Chromosome
chemical_list: D001704:Biopolymers; D003470:Culture Media; D003893:Desmin; D005337:Fibrin; D005340:Fibrinogen; D013917:Thrombin