title: Ultrastructural comparison of medial collateral ligament repair after single or multiple applications of GaAlAs laser in rats.
abstract: OBJECTIVE
  To examine single versus multiple applications of a gallium aluminum arsenide (GaAlAs) laser on the ultrastructural morphology of surgically injured medial collateral ligaments (MCLs) in rats.
  
  
  METHODS
  Sixteen rats were studied with 12 receiving right MCL transection and 4 receiving sham injury. Group 1 (n = 4) received one session of laser (31.6 J/cm(2)) immediately after injury. Group 2 (n = 4) received 9 doses of transcutaneous laser (3.5 J/cm(2)). The controls (Group 3, n = 4) received one session of placebo laser, while the sham Group 4 (n = 4) received no treatment. Ultrastructural analyses were done with electron microscopy at 3 weeks.
  
  
  RESULTS
  The mass-averaged diameters of collagen fibril in the core and periphery of MCLs treated with multiple laser were larger than the control and those with single laser treatment (P < 0.05). However, the sham injured group had larger fibrils than all other groups (P < 0.05).
  
  
  CONCLUSIONS
  The repairing MCLs had smaller collagen fibrils than the sham injured ligaments. Multiple laser treatments enhanced the collagen growth in the repairing MCLs at 3 weeks after injury, which are superior to a single treatment with similar dosage.
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. rsgng@polyu.edu.hk
authors.forename: Gabriel Y F
authors.initials: GY
authors.lastname: Ng
authors.forename: Dicky T C
authors.initials: DT
authors.lastname: Fung
authors.forename: Mason C P
authors.initials: MC
authors.lastname: Leung
authors.forename: Xia
authors.initials: X
authors.lastname: Guo
mesh_terms: D000818:Animals; D017885:Collateral Ligaments / Q000601:surgery* / Q000648:ultrastructure*; D053685:Laser Therapy; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley