title: Immunohistological evaluation of skin responses after treatment using a fractional ultrapulse carbon dioxide laser on back skin.
abstract: OBJECTIVE
  Fractional photothermolysis (FP) lasers have been widely used in treating photo-aged skin, acne scars, and other skin conditions. Although plenty of clinical data have demonstrated the efficacy of the FP laser, only limited histologic studies have been available to observe serial short- to long-term skin responses.
  
  
  METHODS
  Seven healthy Chinese women received one pass of fractional carbon dioxide laser treatment on the left upper back. Biopsies were taken at the baseline and 4 hours, 1 day, 5 days, 1 month, 3 months, 6 months, and 1 year after the procedure for hematoxylin and eosin stains, immunohistochemical evaluation (for heat shock proteins and elastin), and Verhoeff-iron-hematoxylin stains (for collagen and elastic fiber).
  
  
  RESULTS
  Remarkably greater expression of heat shock protein (HSP)70 could be observed 4 hours after the procedure, which diminished significantly by 3 months, 6 months, and 1 year after the procedure. HSP47 reached its peak expression 1 month after the procedure, especially around microscopic thermal zones, and maintained its high level of expression 3 and 6 months after the procedure. Distinct new formation and remodeling of collagen and elastic fibers could be observed 3 and 6 months after procedure.
  
  
  CONCLUSIONS
  FP-induced HSP expression and new formation of collagen and elastic fibers lasted as long as 6 months, longer than the previously acknowledged 3 months.
authors.affiliation: Department of Dermatology, No. 1 Hospital of China Medical University, Shenyang, China.
authors.forename: Xue-Gang
authors.initials: XG
authors.lastname: Xu
authors.forename: Yao-Jia
authors.initials: YJ
authors.lastname: Luo
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: John Zs
authors.initials: JZ
authors.lastname: Chen
authors.forename: Tian-Hua
authors.initials: TH
authors.lastname: Xu
authors.forename: Xing-Hua
authors.initials: XH
authors.lastname: Gao
authors.forename: Chun-Di
authors.initials: CD
authors.lastname: He
authors.forename: Long
authors.initials: L
authors.lastname: Geng
authors.forename: Ting
authors.initials: T
authors.lastname: Xiao
authors.forename: Ya-Qin
authors.initials: YQ
authors.lastname: Zhang
authors.forename: Hong-Duo
authors.initials: HD
authors.lastname: Chen
authors.forename: Yuan-Hong
authors.initials: YH
authors.lastname: Li
mesh_terms: D003094:Collagen / Q000378:metabolism; D020405:Dermis / Q000378:metabolism / Q000473:pathology* / Q000528:radiation effects; D019583:Dose Fractionation, Radiation; D004549:Elastin / Q000378:metabolism; D004817:Epidermis / Q000378:metabolism / Q000473:pathology* / Q000528:radiation effects; D005260:Female; D050958:HSP47 Heat-Shock Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D054020:Lasers, Gas; D028022:Low-Level Light Therapy; D008875:Middle Aged; D013997:Time Factors
chemical_list: D050958:HSP47 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D003094:Collagen; D004549:Elastin