大鼠颈椎间盘退行性变后软骨细胞凋亡及形态学改变

背景椎间盘软骨终板是椎间盘营养渗透的主要途径,又是维持脊柱生物力学的重要结构之一.对其重要性的认识及相关研究日益深入,但对椎间盘退行性变的确切原因仍不清楚.目的动态观察大鼠颈部动静力失去平衡后颈椎间盘软骨细胞凋亡的形态学改变以及凋亡率.设计采用完全随机对照设计.地点和对象实验在上海中医药大学脊柱病研究所完成,对象为8月龄清洁级SD大鼠60只,雌雄各30只.干预将雌雄大鼠分别按随机数字表法分为3,5,7月对照组与模型组,每组10只,雌雄各5只.取大鼠颈背部正中纵向切口,切开皮肤后,充分游离各层肌肉,横向切断深群颈夹肌和头、颈、寰最长肌,完全切除颈髂肋肌与头半棘肌,然后再依次切断C2～C7棘上和棘间韧带,建立的动静力失衡性颈椎间盘退行性变模型.主要观察指标3,5,7月后椎间盘软骨细胞凋亡程度.结果退行性变椎间盘内有典型凋亡的软骨细胞.与对照组比较,各个模型组软骨细胞凋亡指数明显升高(P＜0.01);模型组间比较,TUNEL法5,7月软骨细胞凋亡指数分别为36.59±5.93和3636±5.13较3月(27.73±4.12)明显升高(P＜0.01),流式细胞仪PI法5,7月细胞凋亡指数分别为37.56±3.82和28.02±3.48较3月(21.45±2.23)明显升高(P＜0.01).结论退行性变椎间盘软骨终板内软骨细胞凋亡数目增多,这可能是椎间盘退行性变的重要机制之一.

Chondrocyte apoptosisand morphological changes of degenerated cervical intervertebral disc in rats

BACKGROUND: The cartilage endplate of intervertebral disc, the main way of the nutrition pervasion in intervertebral disc, is also one of the important structures in maintaining the biodynamics of spine. Though its importance and related researches were recognized further, the actual reasons for degeneration of intervertebral disc still remains unclear.OBJECTIVE: To dynamically observe the morphological changes of the chondyrocyte apoptosis and the apoptotic rate of chondyrocytes in the degenerated intervertebral disc after imbalance of dynamic and static force was established in the cervix of rats.DESIGN: A completely randomized controlled study.SETTING and PARTICIPANTS: The study was conducted in the Research Institute of Spine, Shanghai University of Traditional Chinese Medical. Subjects were sixty 8-month-old SD rats with 30 rats in each gender (clean grade).INTERVENTIONS: Male and female rats were randomly allocated into 3-,5- and 7-month control groups and 3-, 5- and 7-month model groups with 10rats each(5 in each gender) by means of random number table. Skin was cut in the medium of the cervical back in rats. Each layer of muscle was separately adequately. The deep cervical splenius muscle and the longest muscles of head, cervix and neck were cut crossly. Iliocostalis cervicis and semispinalis capitis muscles were completely cut. The supraspinal and interspinal ligaments were cut off from C2 to C7 in turn. After the procedures,the rat model of degeneration in cervical intervertebral disc caused by imbalance between the dynamic and static force was set up.MAIN OUTCOME MEASURES: The degree of chondrocyte apoptosis in intervertebral disc at 3, 5 and 7 months respectively.RESULTS: There was typical chondrocyte apoptosis in degenerated cervical intervertebral disc. The index of apoptosis was significantly higher in the disc of each model groups compared with each control groups respectively (P＜0.01) . The apoptotic indices were significant higher in 5- and 7-month model groups[ (36.59±5.93) and (36.36±5.13) respectively]compared with that of 3-month model group(27.73±4.12,P＜0.01) by TUNEL method, and the apoptotic indices were significantly higher in 5-month and 7-month model groups[ (37.56±3.82) and (28.02 + 3.48)respectively] compared with that of 3-month model group(21.45 + 2.23, P ＜0.01) analyzed by flow cytometry.CONCLUSION: There are much more apoptotic cells in cartilage endplate of degenerated cervical intervertebral discs, which may be one of the important mechanism of degeneration of cervical intervertebral disc.