Establishment of lumbar intervertebral disc degeneration rabbit models and the imageological changes

Xingang ZHAO; Jian SHI; Tiesheng HOU

ABSTRACT

BACKGROUND:

The establishment of animal models is of important significance for understanding the pathogenesis, prevention, and treatment of intervertebral disc degeneration.

OBJECTIVE:

To develop rabbit models of intervertebral disc degeneration by acupuncture and to analyze the effects of acupuncture on intervertebral disc height and degeneration by X-ray and MRI examinations.

DESIGN:

A randomized and controlled observation.

SETTING:

Department of Orthopaedics, Changhai Hospital, Second Military Medical University of Chinese PLA. MATERIALS This study was performed at the Animal Cener, Changhai Hospital, Second Military Medical University of Chonese PLA between June 2005 and April 2006. Six healthy New Zealand white rabbits of either gender, averaging 6 months old, weighing 2.5 kg on average, were provided by Animal Cener, Changhai Hospital, Second Military Medical University of Chinese PLA [permission No. SCXK (hu) 2002-0006], and recruited for this study. The protocol was performed in accordance with ethical guidelines for the use and care of animals.

METHODS:

① Operation was made in experimental rabbits via the anterior retroperitoneal approach. The management for the intervertebral discs was as follows L3-4 was the control disc without exposure or needle stab; L4-5 was subjected to sham-operation with only exposure; L5-6 was the experimental disc with three times of anterior-lateral needle stab after exposure. Lumbar lateral X-ray film was respectively taken with a CR machine (Simens Company) prior to and 4 weeks after surgery for measuring L3-4, L4-5, and L5-6 intervertebral disc height and calculating the ratio with intervertebral disc height prior to surgery. Each segmental lumbar intervertebral disc T2-weighted signal was measured with a 1.5 T medical superconductive magnetic resonance scanner (Simens Avanto). According to signal intensity, intervertebral disc degeneration was graded a score of 4 indicated normal intervertebral disc without apparent degeneration but with bright signal, a score of 3 indicated slight degeneration with a little decrease in T2-weighted signal, a score of 2 indicated moderate degeneration with apparent decrease in T2-weighted signal, and a score of 1 indicated severe degeneration with apparent decrease in both T2-weighted signal and intervertebral disc height. MAIN OUTCOME

MEASURES:

Intervertebral disc height change revealed by lumbar lateral X-ray film; Intervertebral disc degeneration degree analyzed through magnetic resonance imaging (MRI) examination.

RESULTS:

All 6 experimental rabbits were included in the final analysis. The postsurgery-to-presurgery ratio of intervertebral disc height was 0.982 5±0.017 08 and 0.972 5±0.017 08 for L3-4 and L4-5 respectively, which was higher compared to that for L5-6 (0.550 0±0.02 582). Significant statistical difference existed (P ＜ 0.01). T2-weighted singal score was (4.00±0.0) and (3.75±0.5) for L3-4 and L4-5 intervertebral disc, respectively, which was higher compared to that for L5-6 intervertebral disc. Significant statistical difference existed (P ＜ 0.01).

CONCLUSION:

After 4 weeks of acupuncture, intervertebral disc height is decreased and interterbral disc degeneration obviously appears.