退变腰椎间盘髓核组织中NDRG2表达的变化及其意义

Role of NDRG2 in degenerated human lumbar intervertebral disc tissues

[目的]研究退变的腰椎间盘髓核组织中NDRG2表达的变化及其在椎间盘退变中的作用。[方法]收集腰椎间盘标本47例,根据Pfirrmann分级分为Ⅰ~Ⅴ级。采用免疫组织化学染色、实时-定量PCR（RT-PCR）和Western-Blotting技术从细胞、蛋白和基因水平分别检测腰椎间盘髓核组织中NDRG2的表达,并与Pfirrmann分级进行相关性分析;通过RT-PCR分析P53 mRNA的表达;采用衰老相关的β-半乳糖苷酶（SA-β-gal）实验检测腰椎间盘髓核组织中衰老髓核细胞比例,并与NDRG2表达量进行相关性分析。[结果]免疫组织化学染色、RT-PCR及Western-Blotting检测示NDRG2表达随椎间盘退变程度加重而增加,且与Pfirrmann分级呈正相关;P53 mRNA在腰椎间盘髓核组织中的相对表达随着椎间盘退变程度加重而增加,且与NDRG2的表达量呈正相关。SA-β-gal阳性细胞比例在椎间盘髓核组织中随退变程度加重而增加,并且与NDRG2阳性细胞比例呈正相关。[结论]NDRG2参与了腰椎间盘退变的病理过程,并且可能通过介导腰椎间盘髓核细胞衰老对椎间盘退变起促进作用。

[ Objective ] This study was designed to investigate the expression and significance of N - myc downstream - regulated gene 2 （NDRG2） in degenerated human lumbar intervertebral disc tissues. [ Methods] Forty - seven lumbar interver- tebral disc samples were obtained from patients and divided into 5 groups （ I - V） according to the Pfirrmann grade. NDRG2 ex- pression in the nucleus pulposus was determined by immunohistochemistry, real -time polymerase chain reaction （RT- PCR） , and western - blotting. P53 mRNA level was measured by RT - PCR. Cell senescence was examined by using a senescence - as- sociated - galaetosidase （ SA - gal） assay. [ Results ] NDRG2 level was upregulated along with the severity of inteivertebral disc degeneration, and its expression was positively correlated with the Pfirrmann grade. P53 mRNA level increased in degenera- ted human lumbar intervertebral disc tissues and was positively correlated with that of NDRG2. The percentage of SA - - gal - positive cells was upregulated along with the severity of intervertebral disc degeneration and positively correlated with the number of NDRG2 - positive cells. [ Conclusion ] The upregulation of NDRG2 expression in the nucleus pulposus is involved in the pathological process of lumbar disc degeneration and increases its incidence probably via increasing cell senescence.