title: In vitro biomechanical strain regulation of fibroblast wound healing.
abstract: BACKGROUND
  Strain-directed therapy such as vacuum compression and manual manipulative therapies are clinically effective, but their cellular and molecular mechanisms are not well understood.
  
  
  OBJECTIVE
  To determine the effects of modeled myofascial release (MFR) on fibroblast wound healing and to investigate the potential role of nitric oxide (NO) in mediating these responses.
  
  
  METHODS
  Using an in vitro scratch wound strain model, the authors investigated human fibroblast wound healing characteristics in response to injurious repetitive motion strain (RMS) and MFR. Secretion of NO was induced with interleukin-1β and sodium nitroprusside and inhibited with NO synthase inhibitor L-N(G)-monomethyl arginine citrate (L-NMMA) to determine the effects of NO on wound healing. Protein microarray was also performed to evaluate the expression of intracellular protein and activation of protein kinase G (PKG), extracellular signal-regulated kinase (ERK1/2), protein kinase C (PKC), and phosphoinositide 3-kinase (PI3K), the downstream effectors in the NO pathway.
  
  
  RESULTS
  Fibroblasts that received RMS resulted in reduced wound closure rates (vs nonstrain, P<.05), which are partially attenuated by a single dose of MFR. Interleukin-1β and exogenous NO did not appear to have an effect on nonstrained fibroblast wound healing. However, strained fibroblasts appeared to express increased sensitivity to NO. The authors also observed a 12.2% increase in NO secretion, an increase in PKG activation, and a downregulation of PKC and PI3K inhibitory domain in the combined strain group.
  
  
  CONCLUSIONS
  If clinically translatable, these data suggest that mechanical strain such as vacuum compression therapy and manual manipulative therapy may modify PKC and PI3K to sensitize fibroblasts to NO and improve wound healing by promoting cell proliferation and migration by means of PKC and PKG signaling.
authors.affiliation: University of Arizona College of Medicine-Phoenix, HSEB, Room B558, 435 N 5th St, Phoenix, AZ 85004-2157. standley@email.arizona.edu.
authors.forename: Thanh V
authors.initials: TV
authors.lastname: Cao
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hicks
authors.forename: Paul R
authors.initials: PR
authors.lastname: Standley
mesh_terms: D001696:Biomechanical Phenomena; D005347:Fibroblasts / Q000502:physiology*; D006801:Humans; D026201:Musculoskeletal Manipulations; D009569:Nitric Oxide / Q000502:physiology*; D058539:Phosphatidylinositol 3-Kinase / Q000502:physiology; D011493:Protein Kinase C / Q000502:physiology; D014618:Vacuum; D014945:Wound Healing / Q000502:physiology*
chemical_list: D009569:Nitric Oxide; D058539:Phosphatidylinositol 3-Kinase; D011493:Protein Kinase C