Xia Maosheng, Zhu Yue
Department of Orthopaedics, The First Hospital of China Medical University, Shenyang, PR China.
Connect Tissue Res. 2008;49(6):464-9. doi: 10.1080/03008200802325425.
Integrins are a class of cell adhesion molecules that regulate interactions between cells and their extracellular matrix (ECM). Several specific integrin receptors have been identified in intervertebral discs, including the fibronectin-binding integrin receptors alpha(5) beta(1), alpha(v) beta(3) and the collagen-binding integrin receptors alpha(1) beta(1), alpha(2) beta(1), and, alpha(v) beta(1). But the integrins expressions in degenerated intervertebral discs are still unknown. In our study, the expressions of alpha(1), alpha(2), alpha(5), alpha(v), beta(1), beta(3) integrin subunits, collagens, and fibronectin in normal and herniated intervertebral discs of human were determined. Specimens of human lumbar intervertebral discs were divided into 3 groups: normal discs (n = 10), protrusion (n = 15), and extrusion (n = 15). Real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunoprecipitation were used to evaluate the alpha(1), alpha(2), alpha(5),alpha(v), beta(1), and beta(3) integrin subunits messenger ribonucleic acid (mRNA) and protein expressions. RT-PCR was also performed to measure the mRNA level of collagen I, collagen II, and fibronectin. The expressions of alpha(5) and beta(1) subunits were increased in herniated discs, especially in the discs of extrusion. But as to alpha(1), alpha(2), alpha(v) and beta(3), their expressions had no difference among the discs. Fibronectin, whose binding integrin receptor was alpha(5) beta(1) was also increased. And in herniated discs, the collagen I was increased, but the collagen II was decreased. The expressions of some integrin subunits were increased in herniated discs. These results may be attributed to the interaction between cells and the ECM in the process of degeneration.
整合素是一类细胞黏附分子，可调节细胞与其细胞外基质（ECM）之间的相互作用。在椎间盘中已鉴定出几种特定的整合素受体，包括纤连蛋白结合整合素受体α(5)β(1)、α(v)β(3)以及胶原结合整合素受体α(1)β(1)、α(2)β(1)和α(v)β(1)。但整合素在退变椎间盘中的表达情况仍不清楚。在我们的研究中，测定了人正常和突出型椎间盘组织中α(1)、α(2)、α(5)、α(v)、β(1)、β(3)整合素亚基、胶原和纤连蛋白的表达。人腰椎间盘标本分为3组：正常椎间盘（n = 10）、突出型（n = 15）和脱出型（n = 15）。采用实时定量逆转录聚合酶链反应（RT-PCR）和免疫沉淀法评估α(1)、α(2)、α(5)、α(v)、β(1)和β(3)整合素亚基信使核糖核酸（mRNA）和蛋白表达。还通过RT-PCR检测了I型胶原、II型胶原和纤连蛋白的mRNA水平。α(5)和β(1)亚基在突出型椎间盘中表达增加，尤其是在脱出型椎间盘中。但α(1)、α(2)、α(v)和β(3)在各组椎间盘中的表达无差异。其结合整合素受体为α(5)β(1)的纤连蛋白也增加。在突出型椎间盘中，I型胶原增加，而II型胶原减少。突出型椎间盘中一些整合素亚基表达增加。这些结果可能归因于退变过程中细胞与ECM之间的相互作用。
