Objective:To evaluate the influence of oxygen-ozone on normal nucleus pulposus in cones and the safety of intradiscal oxygen-ozone multipoint injection for the treatment of herniated lumbar disc. Methods:Oxygen-ozone at 40 μg/ml was injected into selected lumbar discs(3 ml) and the paraspinal space(2 ml) with 20G Chiba needle under fluoroscopy in twenty cones. Every cone was given multipoint injection in L5-6 and one point injection in L4-5 respectively. The whole cones were given one time oxygen-ozone injection and were sacrificed for pathology one week, two weeks, three weeks and four weeks respectively after the procedure, specimens in nucleus pulposus were observed macroscopically and microscopically. Results:No serious behavior abnormalities were observed in all animals. The atrophy of nucleus pulposus could be observed one week after oxygen-ozone injection due to significant reduction of water. The nucleus pulposus turned to dry up and looked like gray cheese after four weeks. There was an apparent difference on the cell count of nucleus pulposus between the selected L4-5 and L5-6 intervertebral disc. The cell counting of nucleus pulposus in the L5-6 intervertebral disk decreased obviously. Conclusion:It is suggested that percutaneous intradiscal oxygen-ozone injection at 40 μg/ml is a safe method, and can cause gradual atrophy of nucleus pulposus. The effect on atrophy of nucleus pulposus by multipoint injection model is better than by one point injection. This study provides the evidence of the feasibility and value of this procedure’s dinical application.