title: Amniotic membrane reduces wound size in early stages of the healing process.
abstract: OBJECTIVE
  To investigate the effects of dispase de-epithelialised, glycerol cryopreserved amniotic membrane (AM) on full-thickness skin defects, using a rat model.
  
  
  METHODS
  Skin defects of 15 mm diameter were surgically created and measured on the scalps of 53 male rats. Animals were divided into two groups and followed for 0, 3, 7, 14 or 21 days. AM group wounds were covered with de-epithelialised AM and sodium chloride-moistened Aquacel (ConvaTec Inc.); control group wounds were covered with sodium chloride-moistened Aquacel alone. After the follow-up, wounds were measured again, serum samples were taken and wound sites were harvested for histological analysis. Systemic interleukin-4 (IL-4) levels were analysed from serum.
  
  
  RESULTS
  On day 3, a statistically significant difference (p < 0.01) was observed in mean wound size, with wound size in the AM group smaller than in the control group (60 ± 12% vs 81 ± 13% of the original size); other time points showed no significance difference in wound size between the two groups. We could not detect differences between the groups in histological parameters or serum IL -4 levels.
  
  
  CONCLUSIONS
  According to this study, AM enhances early stage wound healing in terms of wound size but its effect decreases in later phases. The IL-4 results provide no clear evidence that IL-4 contributes to the effect of AM on wound healing.
  
  
  BACKGROUND
  This study was financially supported by the Competitive Research Funding of the Tampere University Hospital (Grant 9H041, 9J047). The authors have no additional conflicts of interest to declare.
authors.affiliation: Institute of Biomedical Technlogy, University of Tampere, Finland. panu.nordback@uta.fi
authors.forename: P H
authors.initials: PH
authors.lastname: Nordback
authors.forename: S
authors.initials: S
authors.lastname: Miettinen
authors.forename: M
authors.initials: M
authors.lastname: Kääriäinen
authors.forename: M
authors.initials: M
authors.lastname: Pelto-Huikko
authors.forename: H
authors.initials: H
authors.lastname: Kuokkanen
authors.forename: R
authors.initials: R
authors.lastname: Suuronen
mesh_terms: D000818:Animals; D001684:Biological Dressings; D015847:Interleukin-4 / Q000097:blood; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014945:Wound Healing; D014950:Wounds, Penetrating / Q000628:therapy*
chemical_list: D015847:Interleukin-4