动静力失衡性大鼠颈椎间盘退变模型的动态观察

目的：动态观察大鼠颈部动静力失去平衡后颈椎间盘退变的过程与程度。方法：选择8月龄清洁级SD大鼠60只，随机分为3月、5月、7月3个对照组，3月、5月、7月3个模型组，每组10只。在建立动静力失衡性大鼠颈椎间盘退变模型的基础上（对照组为不作手术的正常大鼠），组织形态学评判颈椎间盘退变的程度；并检测前列腺素E2（PGE2）、6－酮－前列腺素F1α（6－Keto-PGF1α)含量和胶原酶（MMP－1）活性。结果：（1）3月模型组可见颈椎间盘纤维环出现裂隙，排列轻度不规则，髓核出现皱缩或变小，少数间盘可见髓核轻度突出；5月模型组大鼠椎间盘髓核完全纤维化，7月模型组椎间盘突出或骨赘形成。（2）与同期对照组比较，5月和7月模型组大鼠MMP－1活性明显升高（P＜0．05）；PGE2和6－keto-PGF1α含量均明显升高（P＜0．05或P＜0．01）。（3）模型组组间比较，5月和7月组大鼠MMP－1活性比3月组升高（P＜0．05）；5月组6－keto-PGF1α较3月组升高（P＜0．05）。结论：颈椎间盘退变是一渐进性的过程，通过破坏大鼠颈部动静力平衡系统，可以加快颈椎间盘退变进程，从而进一步阐述了“动力失衡为先，静力失衡为主”的颈椎病病机学说。

Dynamic Observation on Imbalance of Dynamic and Static Forces and Degenerated Cervical Intervertebral Disc in Rats

OBJECTIVE: To study the relation between biomechanical imbalance and the degree and course of degeneration of cervical intervertebral disc in rats. METHODS: Sixty SD rats, 8 months old, were randomly divided into 6 groups, the control and model groups of 3, 5, 7 months, 10 in each group. The cervical disc dynamic and static forces imbalance of degeneration model was established to assess the degree of degeneration as well as the content some inflammatory mediators (prostaglandin E2, 6-keto-prostaglandin F1 alpha) and collagenase (MMP-1) activity. RESULTS: (1) In 3 months model group and 5 months control group, fibrous ring of intervertebral disc showed some fissure and slight irregular arrangement, nucleus pulposus shrunken or became smaller, mild herniation of nucleus pulposus was seen in some disc. The nucleus pulposus of intervertebral disc in 5 months model group was fibrosed completely and the disc in 7 months model group herniated or became osteophytosis. (2) Compared with the control group of same time period, MMP-1 was increased significantly in the 5 months and 7 months model groups (P < 0.05), and prostaglandin E2 and 6-keto-prostaglandin F1 alpha elevated in the model groups (P < 0.05, P < 0.01). (3) Comparison between model groups, MMP-1 activity in 5 months and 7 months groups was higher than that in the 3 months group (P < 0.05), and 6-keto-prostaglandin F1 alpha was higher in 7 months group than that in 3 months group (P < 0.05). CONCLUSION: Cervical intervertebral disc undergoes a progressive degenerating process. By breaking the dynamic-static balance of neck in rats could accelerate the progression of degeneration. The fact could be used to elucidate the theory of pathogenesis of cervical spondylopathy, dynamic force imbalance in priority and static force imbalance in predominance.