title: Muscle reorganisation through local injection of stem cells in the diaphragm of mdx mice.
abstract: BACKGROUND
  The diaphragm is the major respiratory muscle affected by Duchenne muscular dystrophy (DMD) and is responsible for causing 80% of deaths. The use of mechanical forces that act on the body or intermittent pressure on the airways improves the quality of life of patients but does not prevent the progression of respiratory failure. Thus, diseases that require tissue repair, such as DMD, represent a group of pathologies that have great potential for cell therapy. The application of stem cells directly into the diaphragm instead of systemic application can reduce cell migration to other affected areas and increase the chances of muscle reorganisation. The mdx mouse is a suitable animal model for this research because its diaphragmatic phenotype is similar to human DMD. Therefore, the aim of this study was to assess the potential cell implantation in the diaphragm muscle after the xenotransplantation of stem cells.
  
  
  METHODS
  A total of 9 mice, including 3 control BALB/Cmice, 3 5-month-old mdx mice without stem cell injections and 3 mdx mice injected with stem cells, were used. The animals injected with stem cells underwent laparoscopy so that stem cells from GFP-labelled rabbit olfactory epithelium could be locally injected into the diaphragm muscle. After 8 days, all animals were euthanised, and the diaphragm muscle was dissected and subjected to histological and immunohistochemical analyses.
  
  
  RESULTS
  Both the fresh diaphragm tissue and immunohistochemical analyses showed immunopositive GFP labelling of some of the cells and immunonegativity of myoblast bundles. In the histological analysis, we observed a reduction in the inflammatory infiltrate as well as the presence of a few peripheral nuclei and myoblast bundles.
  
  
  CONCLUSIONS
  We were able to implant stem cells into the diaphragm via local injection, which promoted moderate muscle reorganisation. The presence of myoblast bundles cannot be attributed to stem cell incorporation because there was no immunopositive labelling in this structure. It is believed that the formation of the bundles may have been stimulated by cellular signalling mechanisms that have not yet been elucidated.
authors.affiliation: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, Cidade Universitária, São Paulo, SP, Brazil. thaisblessa@usp.br
authors.forename: Thais Borges
authors.initials: TB
authors.lastname: Lessa
authors.forename: Rafael Cardoso
authors.initials: RC
authors.lastname: Carvalho
authors.forename: André Luis Rezende
authors.initials: AL
authors.lastname: Franciolli
authors.forename: Lilian Jesus
authors.initials: LJ
authors.lastname: de Oliveira
authors.forename: Rodrigo Silva da Nunes
authors.initials: RS
authors.lastname: Barreto
authors.forename: David
authors.initials: D
authors.lastname: Feder
authors.forename: Fabiana Fernandes
authors.initials: FF
authors.lastname: Bressan
authors.forename: Maria Angélica
authors.initials: MA
authors.lastname: Miglino
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Ambrósio
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D003964:Diaphragm / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018101:Mice, Inbred mdx; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D032448:Myoblasts, Skeletal / Q000378:metabolism*; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000378:metabolism / Q000502:physiology*