TGF-β1/Smad2/3通路介导的TIMP-3表达抑制对椎间盘内炎症发生及血管形成的作用研究

Intervertebral disc degeneration (IDD) is thought to be a significant contributor to the development of LBP, which is the main cause of lower quality of life. The vascular infiltration and inflammation were considered to be related with IDD. TIMP3 was reported to have anti-inflammation and anti-angiogenesis abilities in various cells. We found that the expression of TIMP3 in nucleus pulposus cell was inhibited in IDD, and the inhibition of TIMP3 expression was closely related with vascular infiltration and inflammation. To furtherly detect the role of TIMP3 expression in IDD, we systematically investigate the relation between the TIMP3 expression and IDD by in vitro, in vivo model and human tissue specimens. Then, we use a lentivirus vector to study the potential therapeutic effect of the upregulation of TIMP3 gene expression in vivo and in vitro. We attempt to clarify that down expression of TIMP3 in nucleus pulposus cell was mediated by TGF-β1/Smad2/3 pathway, and may promote vascular infiltration and inflammation in intervertebral disc. Taken together, our study aims to investigate the relationship and mechanism between TIMP3 expression in nucleus pulposus cells and IDD, thus indicating a new therapeutic target for IDD in the future.

椎间盘退变引发的相关疾病是影响患者生活质量的主要原因之一。既往研究发现椎间盘退变与椎间盘内血管生成及炎症反应密切有关系。基质金属蛋白酶抑制因子-3（TIMP3）被证实在多种细胞中发挥着抗炎及抑制血管生成的作用。我们的研究发现在退变椎间盘内髓核细胞存在TGF-β1/Smad2/3通路介导的TIMP3表达抑制，并且这种表达抑制与椎间盘内炎症发生、血管生成存在密切关系。为进一步明确髓核细胞TIMP3表达抑制在椎间盘退变中的作用，本课题系统性的通过细胞、动物模型及人体组织标本研究髓核细胞TIMP3表达与椎间盘退变的联系，并且通过慢病毒载体在细胞及动物模型上过表达TIMP3，试图明确TGF-β1/Smad2/3通路介导的TIMP3表达抑制是椎间盘内炎症发生及血管形成的重要原因。本研究将阐明髓核细胞TIMP3表达在椎间盘退变中的作用与可能机制，为椎间盘退变的康复治疗提供新的实验依据和理论指导。

椎间盘退变引发的相关疾病是影响患者生活质量的主要原因之一。既往研究发现椎间盘退变与椎间盘内血管生成及炎症反应密切有关系。基质金属蛋白酶抑制因子-3（TIMP3）被证实在多种细胞中发挥着抗炎及抑制血管生成的作用。我们的研究发现在退变椎间盘内髓核细胞存在TGF-β1/Smad2/3通路介导的TIMP3表达抑制，并且这种表达抑制与椎间盘内炎症发生、血管生成存在密切关系: 1.TIMP3表达能够抑制对共培养状态下血管内皮细胞VEGF与VEGFR-2结合力，从而进一步抑制髓核组织内的血管浸润。2. 发现TIMP3表达能够抑制LPS介导的髓核细胞胞外基质降解。3.在上述结果的基础上，在动物模型上发现过表达TIMP3能够抑制粗针头穿刺介导的椎间盘退变，并且减少CD34的含量，即减轻了髓核组织内的血管浸润。4. 进一步的人体标本检测也发现，人体髓核组织中的TIMP3表达与其Pfirrmann分级呈负相关，而MMP3、ADAMTS4的表达却与Pfirrmann分级呈正相关。综上所述，本课题系统性的通过细胞、动物模型及人体组织标本研究髓核细胞TIMP3表达与椎间盘退变的联系，并且通过慢病毒载体在细胞及动物模型上过表达TIMP3，明确了TGF-β1/Smad2/3通路介导的TIMP3表达抑制是椎间盘内炎症发生及血管形成的重要原因。本研究阐明了髓核细胞TIMP3表达在椎间盘退变中的作用与可能机制，为椎间盘退变的治疗提供新的实验依据和理论指导。