Construction and Evaluation for Model of Goat Intervertebral Disc Degeneration Induced by Axial Compressive Stress / 医用生物力学

ABSTRACT

Objective To establish the model of goat intervertebral disc degeneration （IDD） induced by controllable axial compressive stress and evaluate its imaging and pathological characteristics. Methods Twenty goats were randomly divided into 4 groups (control group, 4-week pressure group, 8-week pressure group, 12-week pressure group, n=5, 40 N pressure). Disc height index (DHI) was used to evaluate the change of intervertebral disc height by X-ray, Pfirrmann classification method was used to observe the degree of intervertebral disc degeneration by magnetic resonance imaging (MRI), and histopathological observation and evaluation for intervertebral disc were conducted by HE staining and immunohistochemistry. Results DHI in control group showed no significant changes with the extension of pressure time, while DHI in the experimental group gradually decreased. There was no significant change in Pfirrmann classification in control group. In experimental group, with the extension of time, the higher the degeneration aggravated with the Pfirrmann classification increasing. In experimental group, HE staining showed that the disc nucleus pulposus decreased in volume and nucleus pulposus cells, which were gradually replaced by fibrous tissues. Immunohistochemical staining showed that type I collagen in the nucleus pulposus gradually increased, type Ⅱ collagen gradually decreased, and intervertebral disc degeneration occurred. Conclusions A certain axial compressive stress can lead to degeneration of goat lumbar intervertebral disc, and the degree of degeneration is gradually increased with the extension of time.