title: Structural and biochemical alterations during the healing process of tendons treated with Aloe vera.
abstract: OBJECTIVE
  The tendon is composed of highly organized collagen fibers that form a complex supramolecular structure. After lesions, the organization and composition of the tendon are not completely restored. Our purpose was to evaluate if the application of Aloe vera improves tendon healing, considering the effectiveness in the stimulus of collagen synthesis.
  
  
  METHODS
  The calcaneal tendon of male Wistar rats was partially transected with subsequent topical application of A. vera ointment at the injury. The animals were separated into groups with tendons treated with the A. vera extract for 7days and excised on the 7th, 14th and 21st days after surgery; control rats received only ointment base without plant extract.
  
  
  RESULTS
  Morphological analysis using polarization microscopy showed that the entire tendon undergoes a remodeling process, with disorganized collagen fibers by days 7 and 14 in plant-treated and non-treated groups and with a higher birefringence in tendons of the plant-treated group on the 21st day. A higher concentration of hydroxyproline was found in plant-treated tendons on days 7 and 14 compared with their controls. Western blots showed lower amounts of type I collagen in the plant-treated group on day 14 compared with the control. MMP-9 diminished 14days after lesion and the active isoform of MMP-2 increased on day 21 in plant-treated groups.
  
  
  CONCLUSIONS
  The present study indicates a beneficial effect of A. vera in the tissue reorganization in the transected region of the tendon 21days after injury and is supported by an increase of active MMP-2.
authors.affiliation: Department of Structural and Functional Biology, Institute of Biology, State University of Campinas-UNICAMP, Campinas-SP, Brazil. andreaaro@ig.com.br
authors.forename: A A
authors.initials: AA
authors.lastname: Aro
authors.forename: U
authors.initials: U
authors.lastname: Nishan
authors.forename: M O
authors.initials: MO
authors.lastname: Perez
authors.forename: R A
authors.initials: RA
authors.lastname: Rodrigues
authors.forename: M A
authors.initials: MA
authors.lastname: Foglio
authors.forename: J E
authors.initials: JE
authors.lastname: Carvalho
authors.forename: L
authors.initials: L
authors.lastname: Gomes
authors.forename: B C
authors.initials: BC
authors.lastname: Vidal
authors.forename: E R
authors.initials: ER
authors.lastname: Pimentel
mesh_terms: D000504:Aloe / Q000737:chemistry; D000818:Animals; D003094:Collagen / Q000378:metabolism / Q000648:ultrastructure; D006909:Hydroxyproline / Q000032:analysis; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009824:Ointments; D008517:Phytotherapy / Q000379:methods; D028321:Plant Preparations / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D013708:Tendon Injuries / Q000188:drug therapy; D013710:Tendons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D009824:Ointments; D028321:Plant Preparations; D003094:Collagen; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D006909:Hydroxyproline