The Influence Of Self-designed Controllable Axial Pressure Device Simulating Positive Acceleration Loading On The Rabbit Lumbar Disc

Objective: To estimate the influence of self-designed controllable axial pressuredevice simulating positive acceleration loading on the rabbit lumbar disc, and to providetheoretical foundations for the further study on pilot lumbar disc herniation.Methods: Twenty-four New Zealand white rabbits (4months old) were dividedinto3groups randomly (4rabbits in control group and respectively10rabbits in twoexperimental groups). The self-designed controllable axial pressure device based on2K-wires that punctured through the adjunctive vertebras of corresponding intervertebraldiscs, was utilized to impose40N pressure on the discs for4and8weeks in twoexperimental groups respectively. Ten times in a day and ten seconds at one time. Andno pressure was imposed on the control group. Degeneration of the discs was evaluatedby Thompson’s grading system, magnetic resonance imaging (MRI) scanning,haematoxylin and eosin (HE) staining, and immunohistochemical staining for type I andtype II collagen.Results:①19of24experimental animals met the requirements, which there were7in8weeks group,8in4weeks group and4in control group. The position of2K-wires was good.②Disc height index (％, s) was97.46±0.94in4weeks group, andit was89.08±3.29in8weeks group.③According to the Pfirrmann’s system,3discsreached grade Ⅱ in4weeks group and5discs reached grade Ⅲ in8weeks group.④4discs reached grade Ⅰ in4weeks group and6discs reached grade Ⅱ in8weeks groupby the Thompson’s system.⑤HE staining indicated the degeneration of lumbar disc in8weeks group more serious than that in4weeks group.⑥Immunohistochemicalstaining showed the degeneration of Ⅱ type collagen was consistent with that of HEstaining. TypeⅠ collagen staining showed that distribution of positive stainingincreased in nucleus pulposus. Conclusion: The results of the study suggest that self-designed controllable axialpressure device can be a good choice to simulate positive acceleration loading on therabbit lumbar disc. According to DHI, MRI and pathology results, the lumbar disc ofexperimental group appeared early degeneration, which was more serious as timecontinued. The Benefits of the model are repeatability, stability, reliability, andeconomic practicality, which can provide a good experimental carrier for the furtherstudy of pilot lumbar disc herniation.