title: [High throughout proteomic analysis of non-traumatic osteonecrosis of the femoral head].
abstract: OBJECTIVE
  To explore proteins associated with non-traumatic osteonecrosis of the femoral head in adults by using high throughput proteomic approach.
  
  
  METHODS
  From July 2008 to February 2009, 10 patients with non-traumatic osteonecrosis of the femoral head (7 males, 3 females) and 10 patients with fresh femoral head fracture (5 males, 5 females) who underwent total hip arthroplasty were enrolled randomizedly in the study. The median age was 52 years and 63 years respectively. Necrotic bone tissues were harvested as experimental group from the femoral head of patients with osteonecrosis of the femoral head, and normal bone tissues were collected as the control group from the patients with femoral head fracture. After bone tissues were demineralized, total bone proteins were extracted sequentially by using four different lysis buffers. Thereafter, SDS-PAGE, in-gel digestion and subsequent multi-dimensional liquid chromatography-tandem mass spectrometry (MDLC-MS/MS) were applied to separate and identify the extracted proteins. Different expression level of the proteins in both groups was investigated by TPP software,and different expression protein analysis was then carried out by Turbo SEQUEST. Western blot was applied finally to evaluate the accuracy of mass spectrometry.
  
  
  RESULTS
  The in-depth proteome analysis in experimental and control groups revealed 1 233 and 999 high-confidence proteins with two or more peptides respectively,and the false-positive rate was 0.8%. In total, 192 differentially expressed proteins were identified in experimental samples. At compared with the control, 107 and 53 proteins were identified with the level upregulated and downregulated at least 3 folds respectively. Among them, 34 proteins were found highly associated with osteonecrosis of the femoral head. Downregulated expression of GPCR26 and CHST2, similar with results of mass spectrometry analysis,were confirmed by Western blot in the necrotic bone tissues.
  
  
  CONCLUSIONS
  The pathogenesis of the non-traumatic osteonecrosis of the femoral head has been demonstrated a complicated process and remained unknown. These identified differentially expressed proteins might be promising biomarker candidates for early diagnosis of the devastating disease. This study sheds new light on novel approach to understand the pathogenesis of osteonecrosis of the femoral head.
authors.affiliation: Department of Orthopaedics, the 3rd Affiliated Hospital of Wenzhou Medical College, Wenzhou 325200, Zhejiang, China. denzel_zhang@163.com
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Guo-jing
authors.initials: GJ
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Shi-gui
authors.initials: SG
authors.lastname: Yan
mesh_terms: D015153:Blotting, Western; D002853:Chromatography, Liquid; D005260:Female; D005271:Femur Head Necrosis / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D008297:Male; D008875:Middle Aged; D040901:Proteomics / Q000379:methods*; D053719:Tandem Mass Spectrometry