title: Wound healing differences between Yorkshire and red Duroc porcine medial collateral ligaments identified by biomechanical assessment of scars.
abstract: BACKGROUND
  Currently, there are no large animal models to assess potential genetic contributions to ligament biomechanics during an injury repair response. Yorkshire and red Duroc pigs display phenotypically and genetically different skin wound healing responses; red Duroc skin scars were hyper-contracted and hyper-pigmented, whereas Yorkshire skin scars were not. Such findings raise the question whether connective tissues of synovial joints display a similar differential healing response in these pig breeds. This study assessed medial collateral ligament healing in Yorkshire and red Duroc pigs at the functional (biomechanical) level.
  
  
  METHODS
  Surgical injury was created in the right hind limb medial collateral ligament of Yorkshire and red Duroc pigs. After 10 weeks of healing, low-load (laxity and creep) and high-load (failure) mechanical properties were measured.
  
  
  RESULTS
  Large, complete ligament scars formed by 10 weeks post-injury. A differential healing response was observed between the breeds, where red Duroc ligament scars had larger cross-sectional areas, exhibited greater static and total creep responses, failed at greater deformations and strains (P ≤ 0.05), and failed with strong trends for higher loads and lower moduli (P=0.06) than Yorkshire ligament scars.
  
  
  CONCLUSIONS
  The ligament healing response of red Duroc pigs differs from Yorkshire pigs. Previously observed breed differences in dorsal skin wound healing are not restricted to skin. Such findings support a genetic basis for breed differences in response to connective tissue injury. Since this animal model is physiologically comparable to humans, these findings could provide further insight into identification of specific genetic contributions to ligament repair in human populations.
authors.affiliation: Department of Surgery, McCaig Institute for Bone and Joint Health, Health Research Innovation Centre, University of Calgary, Calgary, AB, Canada. niccole@niccole.net
authors.forename: Niccole M
authors.initials: NM
authors.lastname: Germscheid
authors.forename: Gail M
authors.initials: GM
authors.lastname: Thornton
authors.forename: David A
authors.initials: DA
authors.lastname: Hart
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Hildebrand
mesh_terms: D000818:Animals; D002921:Cicatrix / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D055119:Elastic Modulus; D017888:Medial Collateral Ligament, Knee / Q000293:injuries* / Q000473:pathology / Q000503:physiopathology*; D013045:Species Specificity; D013552:Swine / Q000145:classification* / Q000502:physiology*; D013718:Tensile Strength; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology*