细胞凋亡与大鼠椎间盘纤维环退行性变的关系

Investigation on the Correlation Between Cells Apoptosis and Degeneration of Annulus Fibrosus of Rat Intervertebral Disc

目的:观察增龄和负重对椎间盘纤维环细胞凋亡与形态的影响。方法:通过手术截肢及特殊饲养建立双后肢大鼠模型(实验组),取同龄正常大鼠作为对照组。在第3,6,9,12个月时实验组和对照组分别随机选取8只处死观察,取出L4-5椎间盘及相邻上下椎体组织。椎间盘取材后,行HE染色以及TUNEL染色。计数纤维环活细胞以及凋亡细胞数目,并且观测纤维环破损程度。结果:①凋亡显著出现于纤维环中,随着大鼠月龄的增长凋亡加剧且细胞密度显著降低。实验组纤维环的凋亡率在6个月时较对照组明显增加,实验组6个月、9个月组间比较差异有统计学意义(P<0.05)。②实验组的纤维环结构较对照组发生更严重的退变,细胞显著减少、胶原纤维粗大、走行紊乱、纤维环变薄并伴随裂隙出现。结论:除增龄外,负重是增加纤维环细胞凋亡、加重椎间盘纤维环破损和退变的重要因素。

Objective：To investigate the impact of aging and weight bearing on anulus fibrosus morphology and annulus fibrosus cells apoptosis. Methods：The bipedal rat model was developed by forelimb amputation and special breeding methods. The normal rats of the same age served as the control group. When the rats became 3,6,9 and 12 months old,8 rats randomly selected from each group were sacrificed and paraffin-embedded mid-sagittal sections of the L4-5 spine were obtained. Sections were stained with hematoxylin and eosin and the TUNEL procedure was performed. The numbers of apoptotic cells and viable cells in the anulus fibrosus of the intervertebral discs were counted. The degree of impairment of the anulus fibrosus was evaluated.Results：①Apoptosis appeared in the anulus fibrosus obviously,increased with aging and resulted in a remarkable decrease in cell density. The apoptotic rate of cells within the anulus fibrosus of the bipedal rat model group was significantly higher than the control group at the 6-month time point and a statistically significant difference was observed in the bipedal rat model group between the 6-month time point and 9-month time point （P0.05）.②The structure of the annulus fibrosus degenerated more severely in the bipedal rat model group than in the control group,with the decrease of the viable cells,loss of normal collagen arrangement,the obvious thinning of the annulus fibrosus layer and defects in the structure of the annulus fibrosus. Conclusions：Besides aging,weight bearing is probably a key factor of the increase of anulus fibrosus cells apoptosis and the degeneration of annulus fibrosus of intervertebral disc.