椎体终板软骨细胞凋亡与椎间盘退变的相关性研究

Correlation between chondrocyte apoptosis of vertebral cartilage endplate and degeneration of intervertebral disc

目的探讨椎体软骨终板内软骨细胞凋亡和椎间盘退变之间的关系。方法40只成年新西兰白兔，随机平均分为实验组和对照组。实验组采用阻断椎体软骨终板营养途径的方法制作椎间盘退变模型，对照组不做任何处理。术后4周和8周，每组各处死10只动物，切取软骨终板和相应的椎间盘组织。TUNEL法检测终板软骨细胞的凋亡数，免疫组织化学方法检测椎间盘内Ⅱ型胶原阳性细胞数，并对两组数据进行相关性分析。结果实验组软骨终板内凋亡的软骨细胞在4周、8周时分别为9．9±0、88个／视野和12．4±0、71个／视野，较对照组明显增加，4周、8周组间比较差异有统计学意义（P〈0.05）。相关分析显示，术后4周和8周终板软骨细胞凋亡与Ⅱ型胶原表达之间有高度的相关性，相关系数分别为0．86和0．82（均P〈0.05），表明椎体终板软骨细胞凋亡与椎间盘退变之间存在有高度的相关性。结论阻断椎体软骨终板营养途径可导致椎间盘退变的发生，椎体终板软骨细胞凋亡增加可导致椎间盘内Ⅱ型胶原表达进一步减少。

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 CA 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 ）. Conclusion 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.