三种方法建立大鼠腰椎间盘退变模型

Establishing a rat model of intervertebral disc degeneration using three methods

背景:目前国内外学者对椎间盘退变动物模型进行了大量研究,但尚缺乏公认的最佳实验动物模型,且不同模型之间缺乏系统的比较。目的:通过针刺纤维环法、终板注射法以及两者联合法建立大鼠腰椎间盘退变模型,比较3种方法的造模效果,为椎间盘退变动物模型的选择提供参考。方法:SD大鼠80只,随机等分为4组,分别为针刺组(针刺纤维环)、终板注射组(终板注射无水乙醇)、联合组(即先针刺L5/6纤维环,再用无水乙醇注射同节段上下终板)以及对照组(假手术对照)。分别于术后4,8,12周每组各随机抽取3只动物行X射线检查,测量椎间盘相对高度;取椎间盘组织,行病理学检查及免疫组织化学染色。结果与结论:(1)综合X射线检查、苏木精-伊红染色及免疫组织化学染色结果,除对照组外,针刺组、终板注射组及联合组椎间盘退变均逐渐加重;(2)术后4周,与对照组相比,终板注射组和联合组椎间盘相对高度明显降低,病理学评分明显升高,Ⅰ型胶原染色平均灰度值显著降低(P<0.05);(3)术后8,12周,与对照组相比,其他3组椎间盘相对高度均明显降低,病理学评分均明显升高,Ⅰ型胶原染色平均灰度值均显著降低(P<0.05);与针刺组及终板注射组比较,联合组8周椎间盘相对高度显著降低(P<0.05),12周Ⅰ型胶原染色平均灰度值显著降低(P<0.05);(4)结果表明,3种方法均能诱导椎间盘退变;针刺纤维环法手术操作较简单,造模结果可靠,退变严重程度易于控制,可以满足椎间盘退变的各期研究需要;终板注射法适合于椎间盘退变的病因学研究,较针刺纤维环法较早引起退变,但二者诱导退变程度在后期基本相同;联合法较单一方法可明显加快并加重椎间盘退变,有效缩短实验周期。

BACKGROUND： Numerous studies focus on animal models of intervertebral disc degeneration（IDD）, but criteria for establishing the animal models of IDD have not been confirmed, and there is a lack of systematic comparison among models. OBJECTIVE： To compare the rat models of IDD established by puncturing at annulus, endplate injection and their combination, thus providing reference for IDD model selection. METHODS： Eighty Sprague-Dawley rats were equivalently randomized into four groups： puncturing group（puncturing at the annulus）, endplate injection group（endplate injected with ethyl alcohol）, combination group（puncturing at the L5-6 annulus and endplate injection at the same segment） and sham operation group. Three rats in each group were taken at postoperative 4, 8, and 12 weeks for X-ray examination to measure the disc height; and the discs were removed for histological observation and immunohistochemical staining. RESULTS AND CONCLUSION： The results of X-ray examination, hematoxylin-eosin staining and immunohistochemical staining all showed that the IDD degree was gradually aggravated in all groups except the sham operation group. At postoperative 4 weeks, compared with the sham operation group, in the endplate injection and combination groups, the percent disc height was significantly decreased, the pathological scores were significantly increased and the average gray value of collagen type I was significantly reduced（P 0.05）. At postoperative 8 and 12 weeks, compared with the sham operation group, the percent disc height in the other three groups were all significantly decreased, the pathological score was significantly increased, and the average gray value of collagen type I was significantly decreased（P 0.05）. Compared with the puncturing and endplate injection group, in the combination group, the percent disc height at postoperative 8 weeks was significantly decreased, and the average gray value of collagen type I at postoperative 12 weeks was significantly decreased（P 0.05）. These results suggest that the rat IDD model can be successfully constructed by above three methods. Puncturing at the annulus is easy to operate and control IDD progression, which can be used to study different stages of IDD. Endplate injection is suitable for the etiological study of IDD, and induces IDD earlier than puncturing, but the final results are similar. The combination method can significantly accelerate IDD aggravation, and thus is not time consuming.