Imaging and Morphologic Study of Intervertebral Disc Degeneration Model in Rats with Custom Cage and Hind Limbs
Objective:To explore the imaging and morphological characteristics of rat intervertebral disc degeneration model induced by custom-made cage and bipedal limbs.Methods:The neonatal rats were ligated from the upper humerus with silk thread,and then both forelimbs were amputated.The rats were trained to stand upright,similar to humans,by changing their feeding conditions in special cages that could be raised continuously,forcing them to eat and drink only by standing on their hind legs.Lumbar lateral radiographs and MRI were taken at 2,4,8 and 24 weeks to determine the disc height index and Pfirrmann grade.Tissue sections were prepared and histologically evaluated after HE staining.Results:The imaging test at 2 weeks showed physiological curvature of spine was normal,and no obvious narrowing of vertebral space was observed.While at 24 weeks the vertebral edges became sharper,and the subchondral osteosclerosis,and some osteophytes appeared.On MRI,the disc signal decreased,and in severe cases,"black disc"appears.Pfirrmann grading increased significantly.Histological scores increased continuously.Conclusion:The animal model of intervertebral disc degeneration can be established with custom-made cage and bipeda limbs,which is simulated to the natural degeneration of human,and can be used for the study of intervertebral disc degeneration.