title: Histological and molecular analysis of the long-pulse 1,064-nm Nd:YAG laser irradiation on the ultraviolet-damaged skin of hairless mice: In association with pulse duration change.
abstract: BACKGROUND
  Nonablative lasers have been widely used to improve photodamaged skin, although the mechanism underlying dermal collagen remodeling remains unclear.
  
  
  OBJECTIVE
  To investigate the effects and the molecular mechanisms of long-pulse neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation on dermal collagen remodeling in association with different pulse durations.
  
  
  METHODS
  Five hairless mice were pretreated with ultraviolet B irradiation for 8 weeks. The dorsal quadrant of each mouse was then irradiated twice at 1-week intervals at a pulse duration of 1 ms, 12 ms, or 50 ms, and a constant fluence of 20 J/cm(2). The levels of dermal collagen, mRNAs of procollagens, matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases (TIMPs), and various growth factors were analyzed after 4 weeks.
  
  
  RESULTS
  Long-pulse Nd:YAG treatment increased the dermal collagen level. A substantial increase in the level of procollagens, MMPs, TIMPs, and various growth factors was also observed irrespective of pulse duration, with a trend toward maximal increase at a pulse duration of 12 ms.
  
  
  CONCLUSIONS
  Long-pulse 1,064-nm Nd:YAG laser irradiation promotes wound-healing process, which is characterized by the induction of growth factor expression and subsequent increase in MMPs and TIMPs, followed by matrix remodeling as confirmed by new procollagen production.
authors.affiliation: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Do Young
authors.initials: do Y
authors.lastname: Rhee
authors.affiliation: b Asan Institute of Life Science , Seoul , Korea.
authors.forename: Hong Il
authors.initials: HI
authors.lastname: Cho
authors.affiliation: c Department of Dermatology , Dongtan Sacred Heart Hospital, Hallym University College of Medicine , Hwaseong , Korea.
authors.forename: Gyeong-Hun
authors.initials: GH
authors.lastname: Park
authors.affiliation: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Hye-Rim
authors.initials: HR
authors.lastname: Moon
authors.affiliation: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Sung Eun
authors.initials: SE
authors.lastname: Chang
authors.affiliation: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Chong Hyun
authors.initials: CH
authors.lastname: Won
authors.affiliation: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Joon Min
authors.initials: JM
authors.lastname: Jung
authors.affiliation: b Asan Institute of Life Science , Seoul , Korea.
authors.forename: Ki-Young
authors.initials: KY
authors.lastname: Park
authors.affiliation: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Mi Woo
authors.initials: MW
authors.lastname: Lee
authors.affiliation: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Jee Ho
authors.initials: JH
authors.lastname: Choi
authors.affiliation: a Department of Dermatology , Asan Medical Center, University of Ulsan College of Medicine , Seoul , Korea.
authors.forename: Kee Chan
authors.initials: KC
authors.lastname: Moon
authors.affiliation: d Department of Medical Biotechnology , School of Biomedical Science, Kangwon National University , Chuncheon , Korea.
authors.forename: Deug-Chan
authors.initials: DC
authors.lastname: Lee
authors.affiliation: e Naeum Dermatology and Aesthetic Clinic , Seoul Korea.
authors.forename: Boncheol
authors.initials: B
authors.lastname: Goo
mesh_terms: D000818:Animals; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000235:genetics; D015870:Gene Expression / Q000528:radiation effects*; D053844:Lasers, Solid-State; D008297:Male; D020781:Matrix Metalloproteinase 1 / Q000235:genetics; D019278:Matrix Metalloproteinase 3 / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000235:genetics; D051379:Mice; D008812:Mice, Hairless; D010982:Platelet-Derived Growth Factor / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D012867:Skin / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics; D053773:Transforming Growth Factor beta1 / Q000235:genetics; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D024042:Collagen Type I; D024043:Collagen Type II; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; C560825:Timp1 protein, mouse; D019715:Tissue Inhibitor of Metalloproteinase-1; D053773:Transforming Growth Factor beta1; D016222:Fibroblast Growth Factor 2; D019716:Tissue Inhibitor of Metalloproteinase-2; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9; D020781:Matrix Metalloproteinase 1
keywords: Nd:YAG laser; collagen remodeling; pulse duration; rejuvenation; wound healing