Cervical intervertebral disc degeneration induced by unbalanced dynamic and static forces: a novel in vivo rat model.
METHODS
Establishment of a novel in vivo animal model of cervical spondylosis.


OBJECTIVE
To investigate apoptotic, degenerative, and inflammatory changes occurring in the cervical intervertebral discs of rats.


BACKGROUND
Cervical degeneration occurs as the result of imbalance of both static and dynamic spinal stabilizers. The disc degeneration that occurs is characterized by increased local inflammation and increased apoptosis of intervertebral disc cells.


METHODS
By excising the paraspinal musculature and posterior cervical spinal ligaments of rats, both static and dynamic cervical stabilizers were disrupted. The resultant biomechanical imbalance resulted in biochemical and histologic changes, which were characterized by light microscopy, electron microscopy, immunostaining, enzyme-linked immunosorbent assay, polymerase chain reaction, and in situ hybridization.


RESULTS
Histologic analysis showed characteristic degenerative changes of the intervertebral discs and vertebral endplates following surgery. Ultrastructural examination revealed apoptotic changes, which were verified by immunostaining. Instability also resulted in significant up-regulation of inflammatory factors, as shown by enzyme-linked immunosorbent assay, polymerase chain reaction, and in situ hybridization.


CONCLUSIONS
By creating static and dynamic posterior instability of the cervical spine, this novel model of cervical spondylosis results in rapid intervertebral disc degeneration characterized by increased apoptosis and local inflammation, such as that seen clinically.
Wang
Yong-Jun
YJ
Institute of Spine, ShangHai University of Traditional Chinese Medicine. Shanghai, China. yjwang88@hotmail.com
Shi
Qi
Q
Lu
W W
WW
Cheung
K C M
KC
Darowish
Michael
M
Li
Tian-Fang
TF
Dong
Yu-Feng
YF
Zhou
Chong-Jian
CJ
Zhou
Quan
Q
Hu
Zhi-Jun
ZJ
Liu
Mei
M
Bian
Qin
Q
Li
Chen-Guang
CG
Luk
K D K
KD
Leong
J C Y
JC
D000818:Animals; D017209:Apoptosis; D002574:Cervical Vertebrae / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D017364:Collagenases / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D020287:In Situ Nick-End Labeling; D018836:Inflammation Mediators / Q000378:metabolism; D007403:Intervertebral Disc / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013128:Spinal Osteophytosis / Q000209:etiology* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D019714:Tissue Inhibitor of Metalloproteinases / Q000378:metabolism
D016207:Cytokines; D018836:Inflammation Mediators; D019714:Tissue Inhibitor of Metalloproteinases; D017364:Collagenases