Degeneration of Injured Intervertebral Disc Affected by Anterior Longitudinal Ligament Injury in Rabbits

Abstract

Objective: Spinal trauma can cause simultaneous injury of IVD and ALL. Injury of IVD is an important factor causing intervertebral disc degeneration (IDD). However, the relationship between ALL injury and IDD was rarely discussed before. Therefore, the purpose of this study is to investigate the effect of ALL injury on degeneration of injured IVD. Methods: 32 rabbits were randomly divided into four groups, including Sham group, Group A (simple IVD punctured), Group B (IVD punctured with half transverse injury of ALL) and Group C (IVD punctured with entirely transverse injury of ALL). Then, computed tomography, HE staining, intraoperative exploration, immunohistochemistry and TUNEL staining were used to detect the degenerative changes in corresponding IVD. Results: At 2 weeks postoperative, in response to the extent of ALL injury, the middle height of the punctured intervertebral space was reduced; the IVD structure was disorganized and the number of IVD cells was decreasing; the percentage of IL-1β and TNF-α-immunopositive cells was increasing; the percentage of TUNEL-positive IVD cells was also increasing. And there was significantly different between Group C and other groups in the results of immunohistochemistry and TUNEL (P<0.05). At 8 weeks postoperative, the middle height of intervertebral space was decreased in Group C compared with other groups (P<0.05). Intraoperative exploration found that there was obvious instability of intervertebral space in Group C. Compared with 2 weeks postoperative, the pathological changes were severe; the percentage of immunopositive cells was decreasing; the percentage of TUNEL-positive cells was increasing in the corresponding group. There was significantly different between Group C and other groups in the results of immunohistochemistry and TUNEL (P<0.05). Conclusions: These findings indicated that IVD injury companied with completed ALL injury might cause obvious instability of spine, which might lead to severely corresponding IDD.