title: Rat rotator cuff tendon-to-bone healing properties are adversely affected by hypercholesterolemia.
abstract: BACKGROUND
  Rotator cuff tendon tears represent a major component of reported orthopaedic injuries. In addition, more than one quarter of U.S. adults either currently have high cholesterol levels or have reduced their previously high cholesterol levels through the use of pharmaceuticals. Our clinical data have already linked hypercholesterolemia to full-thickness rotator cuff tears, and experimental data from our laboratory have shown effects on native tendon properties in multiple species. The objective of this study was to evaluate healing of supraspinatus tendons in our rat rotator cuff injury model. We hypothesized that tendon healing would be inferior in rats receiving a high-cholesterol diet for 6 months compared with those receiving standard chow.
  
  
  METHODS
  All animals were subjected to a unilateral supraspinatus detachment and repair surgery, with contralateral limbs serving as within-animal comparative data. Animals continued their respective diet courses, and their supraspinatus tendons were biomechanically or histologically evaluated at 2, 4, and 8 weeks postoperatively.
  
  
  RESULTS
  Biomechanical testing revealed a significant reduction in normalized stiffness in hypercholesterolemic rats compared with controls at 4 weeks after injury, whereas histologic analyses showed no significant differences in collagen organization, cellularity, or cell shape between groups.
  
  
  CONCLUSIONS
  On the basis of our findings, hypercholesterolemia may have a detrimental biomechanical effect on tendon healing in our rat rotator cuff injury and repair model.
  
  
  METHODS
  Basic science study, animal model.
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA; American Sports Medicine Institute, Birmingham, AL, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Beason
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Jennica J
authors.initials: JJ
authors.lastname: Tucker
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA; Department of Orthopaedic Surgery, Spine & Joint Institute Teun Teun Hospital, Goyang-si, Gyeonggi-do, South Korea.
authors.forename: Chang Soo
authors.initials: CS
authors.lastname: Lee
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Lena
authors.initials: L
authors.lastname: Edelstein
authors.affiliation: Rothman Institute, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Abboud
authors.affiliation: McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA. Electronic address: soslowsk@upenn.edu.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Soslowsky
mesh_terms: D000818:Animals; D003094:Collagen; D004195:Disease Models, Animal; D006937:Hypercholesterolemia / Q000150:complications*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017006:Rotator Cuff / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D000070636:Rotator Cuff Injuries; D013708:Tendon Injuries / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D014945:Wound Healing
chemical_list: D003094:Collagen
keywords: Hypercholesterolemia; biomechanics; injury; rat; rotator cuff; shoulder; tendon