title: Mechanical stability affects angiogenesis during early fracture healing.
abstract: OBJECTIVE
  The goal of this study was to determine to what extent mechanical stability affects vascular repair during fracture healing.
  
  
  METHODS
  Stabilized and nonstabilized tibia fractures were created in adult mice. Fracture tissues were collected at multiple time points during early fracture healing. Vasculature in fractured limbs was visualized by immunohistochemistry with an anti-PECAM-1 antibody on tissue sections and then quantified with stereology. Oxygen tension, vascular endothelial growth factor expression, and lactate accumulation at the fracture site were measured. Gene expression was compared between stabilized and nonstabilized fractures by microarray analysis.
  
  
  RESULTS
  We found that new blood vessel formation was robust by 3 days after fracture. Quantitative analysis showed that nonstabilized fractures had higher length density and surface density than stabilized fractures at 3 days after injury, suggesting that nonstabilized fractures were more vascularized. Oximetry analysis did not detect a significant difference in oxygen tension at the fracture site between stabilized and nonstabilized fractures during the first 3 days after injury. Further microarray analysis was performed to determine the effects of mechanical stability on the expression of angiogenic factors. No significant difference in the expression of vascular endothelial growth factors and other angiogenic factors was detected between stabilized and nonstabilized fractures.
  
  
  CONCLUSIONS
  Mechanical instability promotes angiogenesis during early fracture healing and further research is required to determine the underlying mechanisms.
authors: Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, San Francisco General Hospital, University of California at San Francisco, San Francisco, CA 94110, USA.
authors: Chuanyong
authors: C
authors: Lu
authors: Neema
authors: N
authors: Saless
authors: Diane
authors: D
authors: Hu
authors: Xiaodong
authors: X
authors: Wang
authors: Zhiqing
authors: Z
authors: Xing
authors: Huagang
authors: H
authors: Hou
authors: Benjamin
authors: B
authors: Williams
authors: Harold M
authors: HM
authors: Swartz
authors: Celine
authors: C
authors: Colnot
authors: Theodore
authors: T
authors: Miclau
authors: Ralph S
authors: RS
authors: Marcucio
mesh_terms: D000818:Animals; D017102:Fracture Healing / Q000502:physiology*; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D051379:Mice; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism*; D013314:Stress, Mechanical; D013978:Tibial Fractures / Q000503:physiopathology*
chemical_list: D010100:Oxygen