Establishment of animal model of intervertebral disc degeneration induced by TNF-α

Objective:To establish the animal model of intervertebral disc degeneration(IVDD) induced by tumor necrosis factor-α(TNF-α),and investigate the influence of TNF-α on nucleus pulposus tissue.Methods:The nucleus pulposus of intervertebral disc in L₂ to L₆,L_3/4 and L_4/5 in 30 New Zealand white rabbits were injected with 15 μL of 20 ng/μL TNF-α,and set as the experimental group.The nucleus pulposus of intervertebral disc in L_5/6 was injected with 15 μL of PBS,and set as the control group.The non-treatment L_2/3 of rabbit was set as the blank group.Ten rabbits were randomly selected,and detected using X-ray and MRI after 4,8 and 12 weeks of operation,respectively.The nucleus pulposus tissue of rabbits were examined using immunohistochemistry and TUNEL.Results:After 4 to 12 weeks of operation,the height and T2 weighted image signal of intervertebral disc in experimental group gradually decreased under X-ray and MRI,respectively.The results of immunohistochemistry and TUNEL showed that the expression level of typeⅠcollagen and cell apoptosis in experimental group gradually increased with the time extending,the expression level of type Ⅱ collagen gradually decreased,and the differences of which between the control group and blank group was not statistically significant(P>0.05).Conclusions:The IVDD animal model induced by TNF-α is successfully established.The height of intervertebral disc loses under the mediating of TNF-α,and TNF-α can induce the degeneration and apoptosis of nucleus pulposus cells.The microsyringe puncture can not affect the degeneration and apoptosis of nucleus pulposus cells.