退变椎间盘中护骨素水平与Schneiderman分级的关系

Relationship between osteoprotegerin level in the degenerated intervertebral disc and Schneiderman’s classification

背景:护骨素可抑制破骨细胞活性,调节软骨重塑过程,在维持椎间盘软骨组织完整性方面具有重要作用。目的:观察腰椎间盘退行性变患者椎间盘中护骨素的表达及其与病情严重程度的关系。方法:选取64例腰椎间盘退行性变患者及25例椎体爆裂性骨折患者作为研究对象,收集患者术后的椎间盘组织,检测椎间盘中护骨素mRNA和蛋白的水平。以腰椎间盘MRI检查结果为依据,根据Schneiderman分级方法进行分级,并分析椎间盘中的护骨素水平与疾病分级的关系。结果与结论:实时荧光定量PCR及ELISA检测发现腰椎间盘退行性变患者的腰椎间盘组织中护骨素mRNA和蛋白水平均明显高于椎体爆裂性骨折患者(P<0.01)。非条件logistic回归分析表明,升高的护骨素mRNA和蛋白是腰椎间盘退行性变发病的独立危险因子。且护骨素mRNA和蛋白水平均与Schneiderman分级显著正相关(r=0.367,0.412,P<0.01),说明高表达的护骨素参与了腰椎间盘退行性变的发生,并可反映疾病的严重程度。

BACKGROUND： Recent studies show that osteoprotegerin can inhibit the activity of osteoclast and regulate the process of cartilage reshaping. Osteoprotegerin plays a great role in maintaining the integrity of cartilage tissue of intervertebral disc. OBJECTIVE： To determine the expression of osteoprotegerin in the intervertebral disk of the patients with lumbar disc degeneration （LDD）, and then to analyze the relationship between the expression levels of osteoprotegerin and the severity of LDD. METHODS： Sixty-four patients with LDD （LDD group） and twenty-five patients with disc burst fractures （control group） were enrolled in this study. The intervertebral disc tissues were collected after surgery. Then the mRNA expression and protein levels of osteoprotegerin in the intervertebral disk were examined by real-time polymerase chain reaction （PCR）. The protein level of osteoprotegerin was determined by ELISA method. The grade of disc degeneration was classified according to MRI findings by Schneiderman’s classification and the association between the levels of osteoprotegerin and the Schneiderman’s grades was analyzed. RESULTS AND CONCLUSION： The mRNA expression and protein levels of osteoprotegerin in the intervertebral disc in LDD group were significantly higher than that in the control group which were tested by real-time PCR method and ELISA method. Unconditional logistic regression analysis revealed that elevated mRNA expression and protein levels of osteoprotegerin were independent risk factors of the presence of LDD. In addition, the mRNA expression and protein levels of osteoprotegerin were both significantly correlated with Schneiderman’s grades （r =0.367, P 0.001 and r =0.412, P 0.001, respectively）. Patients with higher Schneiderman’s grade showed relatively higher levels of osteoprotegerin. The levels of osteoprotegerin were significantly elevated in the intervertebral disc of patients with LDD and were significantly associated with the severity of LDD.