镁调节软骨细胞nNOS表达水平在骨关节炎中的作用及其机制研究

Osteoarthritis (OA) is a common degenerative joint disease, the pathogenesis of which is still not very clear. Applicant's study found that magnesium can protect chondrocyte, delay the development of OA and suppress the expression of nNOS and NMDAR of human OA chondrocyte. There is evidence in literature that: The expression of nNOS and NMDAR is significantly elevated in OA chongdrocyte than usual levels and NMDAR can upgrade nNOS expression level in neuron; intra-articular injection of magnesium sulfate can relieve OA pain symptoms and inhibit NMDAR activity of cartilage in the animal model. Thus it could be speculated that: magnesium can inhibit the expression and activity of NMDAR in chondrocyte, thus regulate nNOS expression levels to protect the articular cartilage and relieve pain symptoms. This project aims to confirm the above hypothesis in vitro(single and three-dimensional culture) and in vivo, using overexpression transfection, siRNA interference and CRISPR/Cas9 gene-editing technologies, then further explore the down-regulation effect on expression of nNOS by magnesium through phosphorylation of NMDAR-specific sites in chondrocyte, finally reveal the pathogenesis of OA from a brand-new perspective, explore new biological intervention targets and provide new ideas for the prevention and treatment of OA.

骨关节炎（Osteoarthritis，OA）是常见关节退行性疾病，其发病机理尚不十分明确。申请人的研究发现镁可保护软骨细胞、延缓OA发生发展，并可下调人OA软骨细胞nNOS和NMDAR表达水平。结合文献报道：OA软骨细胞较正常软骨细胞nNOS与NMDAR表达水平显著升高，NMDAR可上调神经细胞nNOS表达水平，关节腔内注射硫酸镁可抑制OA动物模型软骨NMDAR活性并缓解疼痛症状，提出假说：镁可抑制软骨细胞NMDAR表达与活性，从而调控nNOS表达水平，最终保护关节软骨并缓解疼痛症状。本项目拟采用过表达转染、siRNA干扰和 CRISPR/Cas9基因编辑等技术，在体外细胞（单层和三维培养）与活体动物两个层面证实以上假说，并进一步探索镁通过影响软骨细胞NMDAR特异性位点的磷酸化从而调控nNOS的表达水平。旨在从全新的视角揭示OA发病机理，探索新的生物学干预靶点，为临床防治OA提供新思路。

骨关节炎（Osteoarthritis，OA）是常见关节退行性疾病，其发病机理尚不十分明确。人群研究提示低镁为 OA 患病的危险因素。本课题通过开展细胞实验和动物实验研究了镁对小鼠骨关节炎软骨损伤的影响，研究了镁可对关节软骨nNOS和NMDAR表达的调控作用，研究了nNOS对软骨细胞基质降解、炎症反应和NMDAR表达的影响，在此基础上进一步探究了镁调控软骨细胞功能的其他可能机制。研究结果明确了nNOS 表达水平对骨关节炎的影响，证实了镁对软骨细胞nNOS和NMDAR表达水平的的影响，验证了nNOS对软骨细胞基质降解、炎症反应和NMDAR表达的影响，表明Mg可通过调控软骨细胞 nNOS表达水平和NMDAR 表达进而影响骨关节炎进展。本项目探究了低镁对骨关节炎进展的影响及其机制，证明了低镁为骨关节炎的危险因素；验证了镁补充对骨关节炎的治疗作用，为今后镁剂补充治疗骨关节炎的转化研究提供了理论依据。