The Study Of Rats Lumbar Facet Joints Degeneration Model Induced By Monosodium Iodoacetate

Objective This study, using a variety of staining and semi-quantitative method, aims to establish an animal model to simulate the process of the degeneration of the lumbar facet joints. Meanwhile, SR-μCT, which has higher resolution, will be used to reconstruct the three dimensional structure of the normal and the degenerated lumbar facet joints. With this technology we can learn the details of the degenerated joints3D structure and provide a new idea to the study of the degeneration of lumbar facet joints.Methods Facet joint degeneration model was established by injecting MIA into the L4/5rat lumbar facet joint. This study can be divided into two groups. One is the control group that injects the same amount of saline. Another group named the degeneration group, which contains3days,7days,14days,21days,28days,35days,42days. Facet joint will be got at each time point and analyzed by histological staining and SR-μCT to verify this model and investigate the morphological changes of facet joint degeneration.Results (1) MIA injection model could successfully simulate the process of the facet joint degeneration.3days group had no significant changes compared with7days group in articular cartilage. The structure of cartilage degenerated rapidly after14days.(2) Modified Mankin’s scores from safranin-O fast green staining showed that, scores in14days,21days,28days,35days and42days had statistically significant differences with the control.(3) Cartilage thickness was measured by toluidine blue staining. The thickness of under facet was gradually thinning with the degeneration.21days group and the following groups had statistical difference compared with the control group. The facet cartilage was hypertrophy in35days group and42days group which have statistical difference compared with the control group.(4) Cartilage cells count was measured by safranin-O fast green staining. Cartilage cells were increased in7days group which had significant differences with the control group, while cells were decreased from14days to42days. Four groups (21days to42days) had significant differences with the control group.(5) SR-μCT could reconstruct the three-dimensional structure of lumbar facet joints, and observe the characteristics of the facet joint degeneration from the overall.(6) With the analysis of different time points of SR-μCT reconstructed. The texture changes and some pores were found in the7days group. The cartilage of14days and21days damaged seriously and had great difficulties to separate and to reconstruct.Conclusion It was found from histological observation that intra-articular injection of sodium iodide method could be successfully induced lumbar facet joint cartilage degeneration model. SR-μCT could observe the lumbar facet joint in a higher-resolution. The three-dimensional reconstruction could observe the whole process of lumbar facet joint degeneration.