[Correlation between chondrocyte apoptosis of vertebral cartilage endplate and degeneration of intervertebral disc].
OBJECTIVE
To investigate the correlation between chondrocyte apoptosis of cartilage endplate and intervertebral disc degeneration.


METHODS
Forty adult New Zealand rabbits were randomized into 2 equal groups: experimental group, undergoing exposure of the upper and lower margins of vertebral bodies C4 and C5, lower ARFIN OF c3, and upper margin of C6, and wadding of bone cement to the depth of posterior margin to interrupt the nutrition supply to the vertebral endplate, thus establishing the models of intervertebral disc degeneration, and control group, only undergoing exposure of the cervical vertebrae. Four and 8 weeks later ten rabbits from each group were sacrificed to obtain specimens of cartilage endplate and tissues of intervertebral disc. TUNEL approach was used to detect the apoptosis of chondrocytes in the vertebral cartilage endplate and immunohistochemistry was used to determine the expression of type II collagen from the intervertebral disc tissues.


RESULTS
Four weeks after the operation the number of apoptotic chondrocytes of the cartilage endplate in the experimental group was 9.9 +/- 0.88/HP, significantly higher than that of the control group (9.7 +/- 0.94/HP, P < 0.05). Eight weeks after the operation the number of apoptotic chondrocytes of the cartilage endplate in the experimental group was 12.4 +/- 0.71/HP, significantly higher than that of the control group (11.7 +/- 0.91/HP, P < 0.05). Four and 8 weeks after the operation, the numbers of type II collagen positive cells of the experiment group were 27.7 +/- 1.52/HP and 19.5 +/- 1.57/HP respectively, both significantly lower than those of the control group (29.6 +/- 1.54/HP and 20.6 +/- 1.40/HP respectively, both P < 0.05). Correlation analysis showed that vertebral cartilage endplate chondrocyte apoptosis was highly negatively correlated with the expression of type II collagen operation 4 and 8 weeks after the operation with the coefficient values of 0.86 and 0.82 respectively (both P < 0.05).


CONCLUSIONS
Chondrocyte apoptosis in vertebral cartilage endplate may result in the decreased expression of type II collagen in intervertebral discs and lead to the degeneration of intervertebral discs.
Xu
Hong-Guang
HG
Department of Orthopedics, Yijishan Hospital, Wannan Medical College, Wuhu 241001, China.
Chen
Xue-Wu
XW
Wang
Hong
H
Lu
Lin-Ming
LM
Liu
Ping
P
Xia
Liang-Zheng
LZ
D000818:Animals; D017209:Apoptosis; D002356:Cartilage / Q000378:metabolism / Q000473:pathology*; D019902:Chondrocytes / Q000378:metabolism / Q000473:pathology*; D024043:Collagen Type II / Q000096:biosynthesis; D020287:In Situ Nick-End Labeling; D007403:Intervertebral Disc / Q000378:metabolism / Q000473:pathology*; D007405:Intervertebral Disc Displacement; D008297:Male; D011817:Rabbits
D024043:Collagen Type II