纤维环穿刺法建立兔椎间盘退变模型

目的:拟建立一个有效的可重复的椎间盘退变模型.方法:取健康成年新西兰大白兔40只,体质量2.5~3.0 kg,雌雄不限,随机分为纤维环穿刺组和对照组,每组20只.经腹膜外入路暴露L4/5、L5/6两个椎间隙,采用21号针头从椎间隙侧前方刺入L4/5、L5/6椎间盘的纤维环,深度控制在5 mm.对照组仅分离暴露椎间盘,不做任何处理.术后1、2、4、6、8周每组随机选取4只兔子行MRI、HE染色及Ⅱ型胶原免疫组化观察退变椎间盘的变化.结果:MRI观察发现,纤维环穿刺组术后椎间盘T2信号强度呈持续减弱趋势,椎间隙高度也不断下降.从术后2周开始两组差异有统计学意义(P<0.05).HE染色观察发现,随着时间进展,纤维环穿刺组髓核细胞逐渐减少,8周时组髓核组织几乎完全变性,被纤维软骨组织替代.Ⅱ型胶原免疫组化染色示,纤维环穿刺组Ⅱ型胶原表达随时间呈进行性下降,从术后第2周开始两组差异有统计学意义(P<0.05).结论:纤维环穿刺法可以诱导兔椎间盘缓慢退变,为深入研究椎间盘退变机制及治疗手段提供可靠的动物模型.

Constructing the rabbit model of intervertebral disc degeneration induced by annulus fibrosus puncture

Objective:To construct an effective and repeated experiment model for intervertebral disc degeneration.Methods: Forty healthy New Zealand white rabbits(male or female,weighing 2.5-3.0 kg) were randomly divided into the experimental group(n = 20) and the control group(n = 20).Intervertebral discs of L4 /5 and L 5 /6 were exposed by extra-peritoneal approach and were punctured in a depth of 5 mm on the L 4 /5 and L 5 /6 segments in the experimental group via an anterolateral approach using a 21 gauge needle from the front side of the intervertebral space.In control group,intervertebral discs were separated and exposed but without further processing.Pathological changes of intervertebral discs underwent MRI observation and histological observation by using HE staining and collagen type Ⅱ immunohistochemical staining.Results: The intensity of T 2 signal in the experimental group was declined and the height of intervertebral space was decreased with the time going.MRI assessment showed significant differences between the experimental group and the control group from the second week on(P < 0.05).The histological analyses revealed the cell number in nucleus pulposus decreased gradually inthe experimental group.At 8 week after operation,nucleus pulposus was almost completely degenerated and replaced by fibrous cartilage tissue.The immunohistochemical analyses showed that the expression of collagen typeⅡ declined in the experimental group with the time going and the significant changes occurred between the experimental group and the control group from the second week on(P < 0.05).Conclusion: The method of annulus fibrosus puncture can eventually induce the degeneration of intervertebral disc,which provides a reliable animal model for the future study of the mechanism of intervertebral disc degeneration and the effectiveness of treatment.