The Level Of The Adjacent Intervertebraes Degenerations Of The Unstable And Degenerative Intervertebral Discs In Animal Experimental Study

Objective: To resarch the degeneration of the adjacent intervertebral discs of the degenerative intervertebral discs by setting up an rabbit lumbar intervertebral degenerative model.Methods: 24 12-month Newzeland rabbits, divided into operating class and control class randomly ,the procedure in the operating group: through an anterior retroperitoneal approach to expose the anterior aspect of lower lumbar vertebra body of the rabbit .made the excision of the nucleus pulposus and respective annular fibrosus .the procedure in the control group: expose the lower lumbar vertebra body without the excison of the nucleus pulposus and annular fibrosus .12,16,20 weeks after the operations ,executed the rabbits.before execution,performed the radiographic examination for the rabbits. After the executions,harvested the L3-4 L5-6 intervertebraes (including respective nucleus pulposus,annular fibrosus and end plate) from the dead rabbits,performed the histological analyses of the end plate and annular fibrosus and radiographic analyses of the lumbar vertebraes.perform the measurement of the alkaline phosphatase(AKP) of the endplate, and the proteoglycan(PG) of the nucleus pulposus.Results: The images of the radiographic examinations of the rabbits indicated that the adjacent intervertebraes degenerated conspicuously in the operating class.the degree of the degeneration deepened by time.under the microscopic visual field:the structure of endplate became disordered, the alignment of the collagen fibers have been destroyed, the collagen fibers collapsed and end plate calcified. the results of the measurements of the alkaline phosphatase(AKP) of the endplate, and the proteoglycan(PG) of the nucleus pulposus indicated that the degeneration of the intervertebrae deepened by time. Conclusion: To set up an lumbar intervertebrae degenerative model of rabbit by performing the excision of the nucleus pulposus and respective annular fibrosus ,speeding up the process of the cartilage end plate degeneration and deepening its degeneration degree.degenerations of adjacent intervertebraes deepened by time.the content of PG of the nucleus pulposus lost too. indicating that the alteration of the stress after the operation caused the degeneration.