Abstract: Objective To study the role of nitric oxide (NO) and nitric oxide synthase (NOS) in the degeneration of rabbit cartilage endplate (CEP). Methods Twenty-four New Zealand rabbits were divided into experiment (n=12) and control (n=12) groups, and in the former group rabbit models of lumbar CEP degeneration was established by resection of all the lumbar supraspinous and interspinous ligaments and excision of part of the zygapophyseal joints followed by detachment of the posterior paravertebral muscles from the lumbar vertebrae. Lumbar X-ray was performed in both groups 12, 24 and 36 weeks after operation, respectively. The content of NO and NOS activity in the CEP were also measured. Results X-ray of the CEP reveal gradual calcification of the cartilage endplate with the elapse of time, which was more obvious in the experiment group. The content of NO and NOS activity was significantly increased in the experiment group after the operation (P<0.05), but their difference between the measurements at 24 and 36 weeks postoperatively was not obvious (P>0.05). Conclusion NO may play an important role in the development and progression of rabbit cartilage endplate degeneration.