椎间隙感染后椎间盘组织及生化成分改变与椎间盘弥散功能的相关研究

The related research between the biochemical composition and diffusion function of the intervertebral disc after discitis

目的研究兔椎间隙感染后不同时间点,椎体软骨终板及髓核组织学改变、生物化学成分变化与椎间盘弥散功能改变的相关性。方法取新西兰兔60只,制作椎间隙感染模型。在术后1、2、4、8、12周,每次随机取椎间隙感染模型兔各8只、对照组兔4只。采用HE染色观察软骨终板组织形态学,免疫组化测定软骨终板下血管内皮生长因子(VEGF)表达,RT-PCR测定髓核组织中Ⅱ型胶原蛋白、aggrecan蛋白mRNA表达,连续动态增强MRI检测椎间盘弥散功能。结果椎间隙感染后,软骨终板上出现新生毛细血管,VEGF表达逐渐增多,髓核组织内蛋白多糖及Ⅱ型胶原含量减少,软骨终板弥散功能逐渐增强;感染后4周时,新生毛细血管达到最多,VEGF表达最多,弥散功能达到最佳,4周后逐渐减少,在感染后4周时,蛋白多糖及Ⅱ型胶原破坏达到最强,4周后基质破坏有所修复。软骨终板VEGF表达与椎间盘弥散功能呈正相关关系(r=0.704,P=0.000);蛋白多糖mRNA表达与椎间盘弥散功能呈负相关关系(r=-0.480,P=0.000)。结论椎间隙感染后椎间盘弥散功能处于一个动态变化中,在感染后4周时弥散功能达到最佳。椎间隙感染后软骨终板VEGF表达与椎间盘弥散功能呈正相关关系,髓核中蛋白多糖mRNA表达与椎间盘弥散功能呈负相关关系。

Objective To explore the histology and biochemical composition changes of the cartilage end plate and nucleus pulposus during the course of the disease, and the relationship between the above changes and the diffusion function of the endplate cartilage. Methods Sixty New Zealand white rabbits were taken to make discitis model. During the period of 1, 2, 4, 8 and 12 weeks after surgery, 8 discitis rabbits and 4 controls were randomly taken. HE staining of the cartilage endplate histological morphology, immunohistochemical of vascular endothelial cells in the cartilage endplate VEGF expression, real-time polymerase chain reaction （RT-PCR） of the type Ⅱ collagen and aggrecan mRNA expression of the nucleus pulposus and continuous dynamic contrast-enhanced MRI of the diffusion function of the disc were taken. Results The newborn capillaries appeared on the cartilage endplate and the expression of VEGF increased 1-4 weeks after discitis. Proteoglycans and type Ⅱ collagen expression of the nucleus pulposus decreased and the diffusion function of the disc increased gradually. The newborn capillaries, expression of VEGF and the diffusion function achieved the best after 4 weeks and then gradually reduced with the destruction achieving strongest at 4 weeks after infection. A positive correlation existed between the expression of VEGF and the diffuse function（r=0.704, P=0.000）. A negative correlation existed＆amp;nbsp;between the expression of proteoglycan and the diffuse function （r=-0.480, P=0.000）. Conclusion The diffuse function of the intervertebral disc after discitis is in a dynamic change and achieved best in the 4 weeks. A positive correlation existed between the expression of VEGF and the diffuse function. A negative correlation existed between the expression of proteoglycans and the diffuse function.