Objectives： To develop a rabbit model of intervertebral disc degeneration that more exactly simulates the pathological changes of human intervertebral disc degeneration. Methods： Twelve New Zealand white rabbits were utilized to establish three different disc injury models according to the following protocol; group A： anulus punctures were done with a 18-gauge needle at L2-L3 and L5-L6; Group B： intradiscal injection of interleukin-1 IL-1β with a 23-gauge needle at L3-L4; and Group C： intradiscal injection of phosphate buffer saline（PBS） with a 23-gauge needle at L4-LS. The L1-L2 level was used as a control. Rabbits were killed after 24 weeks. The intervertebral disc height was measured by lateral plain radiographs. After the radiographic measurements were obtained, the intervertebral discs were removed and analyzed for DNA, sulfated glycosaminoglycan（s-GAG） and water contents of nucleus pulposus. Results： The intervertebral disc height, s-GAG, and water contents in anulus needle punctures were significantly decreased in Group A, but the DNA content in the nucleus pulposus was significantly increased when compared to the control. The significant decrease of disc height and water contents were demonstrated, only the s-GAG and DNA contents did not show a significant difference in Group B when compared to the control. The significant decrease of disc height, s-GAG, water, and DNA contents did not show in Group C when compared to the control. Conclusion： The 18-gauge puncture models produced the most consistent disc degeneration in the rabbit lumbar spine.
Objective:The age-related change is important part of degenerative disc disease. However,no appropriate animal model or objective evaluation index is available. This study aimed to investigate the features of intervertebral disc degeneration in aging process of rats. Methods:22-month-old Sprague-Dawley(SD) rats were used as spontaneously occurring intervertebral disc degeneration models and 6-month-old rats as young controls. Expression of collagen types II and X was measured by immunohistochemistry. Degenerations of intervertebral discs were scored according to Miyamoto's method. Numbers and areas of afferent vascular buds were measured. The thicknesses of non-calcified and calcified layers were measured and statistically analyzed. Results:There were less collagen type II expression and more collagen type X expression in the calcified layer of the cartilage endplates and nucleus pulposus in the rats of the aged group than in the young control. There were fewer and smaller afferent vascular buds in the rats of the aged group than in the young control group. The ratio of the non-calcified to the calcified layers in the rats of the aged group significantly decreased,compared with that of the young control group(P<0.01) . Conclusion:Rats can spontaneously establish intervertebral disc age-related degeneration. The expression of collagen types II and X,numbers and areas of afferent vascular buds,the ratio of the non-calcified to the calcified layers,and water and glycosaminoglycan contents in the nucleus pulposus are sensitive indexes of intervertebral disc degeneration.
