Expression of hypoxia inducible factor-2 alpha in overloaded- stress induced destruction of mandibular condylar chondrocytes.
OBJECTIVE
To study the protein expression of HIF-2α in condylar chondrocytes under the different stress loading, to investigate the possible effects of HIF-2α involved in the mortality of condylar chondrocytes under overloaded- stress.


METHODS
Chondrocytes were isolated from TMJ condylar cartilage and cultured in hypoxia-incubator. Chondrocytes were divided into 4 groups: 0, 1000, 2000, 3000 ustrain group, which was subjected to cyclic tensile strain (CTS) of 0.5Hz for 2h. The rate of cell mortality was calculated. Western blot was used to measure the expression of HIF-2α and it's downstream catabolic factors (MMP3, MMP13, ADAMTS4) in protein levels respectively.


RESULTS
With the increase of CTS, both of the rate of cell mortality and protein expression of HIF-2α increased significantly (p<0.05). The same tendency was also found in it's downstream catabolic factors (MMP3, MMP13, ADAMTS4) in protein levels (p<0.05).


CONCLUSIONS
The results indicated that elevated expression of HIF-2α may be a possible mechanism related to overloaded- stress induced mortality of condylar chondrocytes.
Stomatology Hospital Affiliated to Medical College, Zhejiang University, China. Electronic address: ewen74@163.com.
Wen
W
Li
The First Affiliated Hospital,Guangzhou University of Chinese Medicine, China.
Yanhui
Y
Liu
Stomatology Hospital Affiliated to Medical College, Zhejiang University, China.
Wanghui
W
Ding
Stomatology Hospital Affiliated to Medical College, Zhejiang University, China.
Tan
T
Long
Stomatology Hospital Affiliated to Medical College, Zhejiang University, China.
Jiejun
J
Shi
D000071121:ADAMTS4 Protein / Q000378:metabolism; D017209:Apoptosis; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D015153:Blotting, Western; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D006801:Humans; D008335:Mandibular Condyle / Q000166:cytology / Q000378:metabolism*; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D013314:Stress, Mechanical; D000099162:Endothelial PAS Domain-Containing Protein 1
D000071121:ADAMTS4 Protein; D051792:Basic Helix-Loop-Helix Proteins; D053509:Matrix Metalloproteinase 13; D019278:Matrix Metalloproteinase 3; D000099162:Endothelial PAS Domain-Containing Protein 1; C000603918:ADAMTS4 protein, human
ADAMTS4; Condylar cartilage; HIF-2α; MMP13; MMP3