脊柱轴线力学失稳诱导椎间盘退变小鼠模型的建立及评价

Establishment and Evaluation of a Mouse Model of Intervertebral Disc Degeneration with Spinal Axial Mechanical Anstability

目的:建立一个操作简单、重复性好、可靠性高的脊柱轴线力学失稳诱导椎间盘退变的小鼠模型并对其进行评价。方法:通过手术去除小鼠棘上和棘间韧带致其脊柱轴线力学失稳来诱导构建椎间盘退变(IDD)模型,并于造模后不同时间点收集腰椎样本,通过番红O/固绿染色观察IDD过程中椎间盘形态学改变,免疫组化法检测椎间盘基质代谢相关蛋白(Col1,Col2和基质降解酶Mmp13)和Hif信号关键蛋白(Hif1α,Vegf)在椎间盘组织中的表达模式变化,对模型进行评价。结果:椎间盘番红O/固绿染色表明,对照组椎间盘组织形态结构完整,内外层纤维环排列整齐,细胞外基质染色均匀;而IDD模型组纤维环出现撕裂、纤维排列紊乱等状况,番红O染色变浅。免疫组化结果表明,对照组椎间盘纤维环中Col1,Col2,Mmp13在正常椎间盘中均有表达。与对照组比较,模型组纤维环中Col2表达显著降低,而Col1和Mmp13表达均显著升高,差异有统计学意义(P<0.05)。Hif信号检测发现,在正常椎间盘组织中,Hif1α于外侧纤维环中呈低表达,后期表达逐渐降低,而Vegf表达于纤维环和髓核组织;与对照组比较,造模4周IDD模型组纤维环组织中Hif1α表达升高,同时伴随Vegf表达的增加,尤其是在内侧纤维环区域,而造模6~8周后,Vegf在纤维环内外侧的表达进一步升高,差异有统计学意义(P<0.05)。结论:应用去除棘上和棘间韧带方式使小鼠脊柱轴线力学失稳,成功建立力学异常IDD小鼠模型。该模型操作简单、重复性好,可为进一步揭示IDD的病理发生机制及临床治疗提供可靠的动物模型。

Objective:To establish and evaluate a simple,reproducible and reliable mouse model of intervertebral disc degeneration induced by spinal axial mechanical instability.Methods:The model of intervertebral disc degeneration(IDD)was established by surgically removing the supraspinal and interspinous ligaments of the mice and causing mechanical instability of the spinal axis.Samples of lumbar vertebrae were collected at different times after model establishment.Morphological changes of intervertebral disc during IDD were observed by safranin O-fast green staining.Immunohistochemical method was used to detect the expression patterns of intervertebral disc Matrix metabolism-related proteins(typeⅠcollagen,typeⅡcollagen and Matrix degrading enzyme Mmp13)and the key proteins of Hif signaling pathway(Hif1α,Vegf)in intervertebral disc tissue.Results:Safranin O-fast green staining showed that morphological structure of intervertebral disc was intact,the inner and outer annulus fibrosus was arranged neatly,and the extracellular matrix was equally stained in control group.The annulus fibrosus was torn and fiber arrangement was disordered,and the safranin O staining became thinner in IDD model group.The immunohistochemical results showed that typeⅠcollagen,typeⅡcollagen,Mmp13 all expressed in normal intervertebral disc of the control group.Compared with the control group,the expression of typeⅡcollagen in the annulus fibrosus of the model group was significantly decreased,while the expression of typeⅠcollagen and Mmp13 were significantly increased(P<0.05).Hif signaling pathway activity detection showed that the low expression of Hif1αwas located in the outer annulus fibrosus in normal intervertebral disc tissue,gradually decreased in the later stage,while the expression of Vegf was located at the the annulus fibrosus and nucleus pulposus tissues.Compared with the control group,the expression of Hif1αand Vegf in the annulus fibrosus tissue,especially in the inner annulus fibrosus had increased in 4 weeks model group.The expression of Vegf in the inner and outer annulus fibrosus had further increased after 6~8 weeks of modeling,and the difference was statistically significant(P<0.05).Conclusion:The lumbar spine instability IDD mouse model has successfully established by removing the supraspinous and interspinous ligaments.The model is simple and reproducible,providing a reliable animal model for further exploring the pathogenesis preclinical treatment of IDD.