title: High glucose concentration up-regulates the expression of matrix metalloproteinase-9 and -13 in tendon cells.
abstract: BACKGROUND
  Diabetes mellitus is associated with tendinopathy or tendon injuries. However, the mechanism underlying diabetic tendinopathy is unclear. The purpose of this study was to examine the effects of high glucose concentrations on the activity and expression of matrix metalloproteinases, type I collagen, and type III collagen in tendon cells.
  
  
  METHODS
  Tendon cells from rat Achilles tendons were treated with 6 mM, 12 mM, and 25 mM glucose, and then cell proliferation was evaluated by the 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Messenger RNA (mRNA) expression of MMP-2, MMP-8, MMP-9, and MMP-13 and type I and type III collagen was assessed by quantitative real-time polymerase chain reaction (PCR). The enzymatic activity of MMP-2 and MMP-9 was measured by gelatin zymography.
  
  
  RESULTS
  The MTT assay results showed that the glucose concentration did not affect tendon cell proliferation. The results of the real-time PCR assay revealed that the mRNA expression of MMP-9 and MMP-13 was up-regulated by treatment with 25 mM glucose, whereas the mRNA expression of type I and III collagen was not affected. Gelatin zymography showed that 25 mM glucose increased the enzymatic activity of MMP-9.
  
  
  CONCLUSIONS
  High glucose concentration up-regulates the expression of MMP-9 and MMP-13 in tendon cells, which may account for the molecular mechanisms underlying diabetic tendinopathy.
authors: Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan. jonghwei@mail.cgu.edu.tw.
authors: Wen-Chung
authors: WC
authors: Tsai
authors: Fang-Chen
authors: FC
authors: Liang
authors: Ju-Wen
authors: JW
authors: Cheng
authors: Li-Ping
authors: LP
authors: Lin
authors: Shih-Chieh
authors: SC
authors: Chang
authors: Hsiang-Hung
authors: HH
authors: Chen
authors: Jong-Hwei S
authors: JH
authors: Pang
mesh_terms: D000125:Achilles Tendon / Q000201:enzymology*; D000818:Animals; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics; D024061:Collagen Type III / Q000235:genetics; D048909:Diabetes Complications / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D005947:Glucose / Q000378:metabolism*; D053509:Matrix Metalloproteinase 13 / Q000235:genetics*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D024042:Collagen Type I; D024061:Collagen Type III; D012333:RNA, Messenger; D053509:Matrix Metalloproteinase 13; C507083:Mmp13 protein, rat; D020780:Matrix Metalloproteinase 9; C572337:Mmp9 protein, rat; D005947:Glucose
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