关节突关节失稳致兔椎间盘退变的分子生物学评价

Molecular biology of intervertebral disk degeneration caused by bilateral zygapophysial joint unstability

目的探讨新西兰大白兔腰椎关节突关节失稳诱发椎间盘退变（IVDD）的蛋白多糖和Ⅰ、Ⅱ型胶原基因的表达。方法30只新西兰大白兔。随机分为骨性手术组和软组织手术组。软组织手术组仅骨膜下剥离L3-L7的椎旁肌肉；骨性手术组完整切除L4、L5双侧下关节突、L5棘突，保留L5、L6上关节突。骨性手术组L4-5、L5-6椎间盘为实验组椎间盘，上下相邻的L3-4、L6-7为自身对照组椎间盘；软组织手术组L4-5、L5-6椎间盘为实验对照组椎间盘。术后1、2、4及8个月处死实验动物，RT—PCR检测椎间盘中蛋白多糖和Ⅰ、Ⅱ型胶原基因表达，并用磷酸甘油醛脱氢酶（GAPDH）做内参照行半定量。结果随着术后时间的延长，各组蛋白多糖、Ⅱ型胶原表达量逐渐下降，Ⅰ型胶原表达量逐渐上升。相同时间段，蛋白多糖、Ⅱ型胶原实验组最低，实验对照组最高（P〈0．01）；Ⅰ型胶原实验组最高，实验对照组最低（P〈0．01）。结论椎间失稳后可以诱发出IVDD。蛋白多糖、Ⅰ、Ⅱ型胶原基因表达能够较早反映出IVDD。

Objective To study aggrecan, collagen type Ⅰ and collagen type Ⅱ gene expression of intervertebral disk degeneration through destroying bilateral zygapophysial joints of New-Zealand rabbit. Methods Thirty male New-Zealand rabbits were randomly divided into operation groups on the bone and operation group on the soft tissue. In operation group of the bone, L4 and L5 inferior articular processes were en bloc excised, L5 and L6 superior articular processes were retained. In the operation group of soft-tissue, only L3 to L7 paravertebral muscles were stripped. In operation group of the bone, L4-5 and L5-6 intervertebral disks were acted as experimental group; L3-4 and L6-7 acted as self-control group. In the operation of soft tissue, L4-5 and L5-6 were acted as experimental control group. One,two,four and eight months post-operation, New-Zealand rabbits were killed. Aggrecan, collagen type Ⅰ and collagen type Ⅱ gene expression were performed with semiquantitative reverse transcriptase polymerase chain reaction （RT-PCR）. Results Aggrecan and collagen type Ⅱ mRNA levels decreased markedly, whereas type Ⅰ collagen mRNA gradually increased. At the same time, aggrecan, collagen type Ⅱ gene expression were the least in experiment group, whereas were most in the experiment-control group. Collagen type Ⅰ showed the contra-tendency. Conclusion Intervertebral disk degeneration can be induced through destroying L4-5 and L5-6 zygapophysial joints of New-Zealand rabbit. Aggrecan, collagen type Ⅰ and collagen type Ⅱ gene expression can reflect intervertebral disk degeneration.