title: Birefringence of collagen fibres in rat calcaneal tendons treated with acupuncture during three phases of healing.
abstract: BACKGROUND
  Birefringence is an optical anisotropy that is investigated by polarisation microscopy, and has been valuable for the study of the oriented organisation of collagen fibres in tendons. However, the application of this technology to evaluate the effect of different acupuncture points during tendon healing has not yet been described.
  
  
  OBJECTIVE
  To evaluate the concentration of non-collagenous proteins (NCP) and birefringence in rat calcaneal tendons following injury during the three different phases of healing: inflammatory (7th day), proliferative (14th day), and remodelling (21st day).
  
  
  METHODS
  Tendons of 120 Wistar rats were tenotomised and left untreated (teno group, n=24), treated with manual acupuncture at ST36 (ST36 group, n=24), BL57 (BL57 group, n=24) or ST36+BL57 (SB group, n=24), or treated with electroacupuncture at ST36+BL57 (EA group, n=24). Tendon samples were collected at 7, 14 and 21 days after injury (n=8 per group). NCP concentrations were measured using the Bradford method (n=4 each) and birefringence was examined using polarisation microscopy and image analysis (n=4 each). Comparison was also made with healthy (non-tenotomised) tendons in a subgroup of rats (n=4 each).
  
  
  RESULTS
  Manual acupuncture at ST36 and BL57 increased molecular organisation of collagen fibres on day 14 and 21 after injury. Isolated use of BL57 and ST36 also increased collagen fibre organisation when examined on day 14 and 21, respectively. No significant increase in NCP concentration was observed in any of the treated tenotomised groups.
  
  
  CONCLUSIONS
  Acupuncture, through putative anti-inflammatory and mechanotransductor effects, may have a role in strengthening tendons and increasing resistance to re-rupture.
authors.affiliation: Department of Anatomy, Biomedical Science Institute, Federal University of Alfenas-UNIFAL-MG, Alfenas, Minas Gerais, Brazil.
authors.forename: Marcos dos Santos
authors.initials: Mdos S
authors.lastname: Almeida
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, State University of Campinas-UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Letícia Prado
authors.initials: LP
authors.lastname: Oliveira
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, State University of Campinas-UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Cristiano Pedrozo
authors.initials: CP
authors.lastname: Vieira
authors.affiliation: Department of Anatomy, Biomedical Science Institute, Federal University of Alfenas-UNIFAL-MG, Alfenas, Minas Gerais, Brazil.
authors.forename: Flávia Da Ré
authors.initials: Fda R
authors.lastname: Guerra
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, State University of Campinas-UNICAMP, Campinas, São Paulo, Brazil.
authors.forename: Edson Rosa
authors.initials: ER
authors.lastname: Pimentel
mesh_terms: D000125:Achilles Tendon / Q000737:chemistry* / Q000293:injuries / Q000378:metabolism / Q000503:physiopathology; D015670:Acupuncture Therapy; D000818:Animals; D001718:Birefringence; D003094:Collagen / Q000737:chemistry / Q000378:metabolism*; D004195:Disease Models, Animal; D006801:Humans; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013708:Tendon Injuries / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D014945:Wound Healing
chemical_list: D003094:Collagen
keywords: ACUPUNCTURE