Constructing a rabbit model of intervertebral disc degeneration induced by puncture and aspiration

Aim: To establish a rabbit model of intervertebral disc degeneration induced puncture and aspiration, and analyze its feasibility and advantage. Methods: The experiment was done from October 2006 to March 2007 at Orthopaedic Laboratory of the First Affiliated Hospital of Soochow University. The L_3-4, L_4-5, and L_5-6 lumbar intervertebral discs of 18 New Zealand white rabbits were stabbed by 21-gauge hypodermic needle into a depth of 5 mm in the anterior annulus fibrosus, then the needle valve was pulled out, and some nucleus pulposus tissues were aspirated out. Immunohistochemical and histologic analyses of the stabbed discs and intact L_2-3 disc (as control group) were performed preoperatively at 4, 8, 12 weeks after surgery. Results: All of 18 rabbits were involved in the result analysis. 1 Histologic analysis: Hematoxylin-eosin dyeing revealed a great deal of cells in nucleus pulposus tissues of control group, and the cells of nucleus pulposus reduced from the fourth week of experimental group, the nucleus pulposus tissues at the twelfth week were mainly fibrocartilage while a little nucleus pulposus cells were found. Type II collagen immunohistochemical analysis: Nucleus pulposus tissue was strongly dyed in control group and presented ebb dye in experimental group. Dye wore off along with the time, this revealed the reduced content of type II collagen in nucleus pulposus tissue. 2 Apoptosis rate of nucleus pulposus cells: The rate was (3±1)% in control group, (17±4)% at the fourth week, (36±2)% at the eighth week and (23±5)% at the twelfth week in experimental group, the difference was significant (F=113.86, P=0.000 1 < 0.01). Conclusion: The aspiration of some nucleus pulposus tissues from the annulus fibrosus by puncture can induce a slowly progressive intervertebral disc degeneration in rabbit model without destroying its immunity barrier. This model is available for studying the intervertebral disc degeneration treatment of mesenchymal stem cells, nucleus pulposus cells and gene transplantation.