A rat caudal vertebral intervertebral disc degeneration model based on cartilage endplate injury
10.3969/j.issn.1004-406X.2025.06.10
- VernacularTitle:终板损伤致大鼠尾椎椎间盘退变模型的研究
- Author:
Chuxin ZHOU
1
;
Dong WANG
1
;
Chu GAO
1
Author Information
1. 空军军医大学第一附属医院骨科 710032 西安市
- Publication Type:Journal Article
- Keywords:
Animal Models;
Cartilaginous endplate injured;
Low back pain;
Intervertebral disc degeneration
- From:
Chinese Journal of Spine and Spinal Cord
2025;35(6):639-647
- CountryChina
- Language:Chinese
-
Abstract:
Objectives:To explore the establishment and validation of a simple and stable model of inter-vertebral disc degeneration(IDD)induced by endplate injury in the rat caudal vertebrae.Methods:32 male Sprague-Dawley(SD)rats,aged 2 months,weighed 180-220g,were used.Among them,24 rats were randomly selected.After anesthesia by intraperitoneal injection,the skin was incised and a scalpel was used to cut a-long the edge of the coccygeal 6(Co6)vertebral bone to injure the unilateral cartilaginous endplate.Specimens were harvested for study on the modeling day(modeling day group),at 2 weeks post-modeling(modeling 2-week group),and at 4 weeks post-modeling(modeling 4-week group).The remaining 8 rats served as a sham surgery group,and the skin was incised with a scalpel and then sutured.The bony endplate was observed using Micro-CT,and sagittal plane images were captured for measurement and calculation of the disc height index(DHI).Hematoxylin and eosin(HE)staining,safranin O-fast green(SO)staining,and TdT-mediated dUTP nick-end labeling(TUNEL)staining were carried on sample slices.The structure of the nucleus pulposus,an-nulus fibrosus,and endplate injury were observed via HE and SO staining.Histological scoring of the inter-vertebral disc was performed using SO staining to evaluate the degree of disc degeneration.Cell apoptosis was observed via TUNEL staining.Results:Micro-CT showed that 2 weeks after modeling,the overall bony struc-ture of the vertebrae remained intact.The endplate thickness increased,and the bony endplate structure was relatively intact,but large areas of defect appeared within it.The vertebrae showed a tendency towards flat-tening,and large osteophytes appeared around them.The DHIs for the sham group,modeling day group,modeling 2-week group,and modeling 4-week group were(9.29±0.74)％,(9.20±1.64)％,(6.05±1.30)％,and(5.10±1.15)％,respectively.Disc space height significantly decreased in both the 2-week and 4-week post-modeling groups compared to the sham group(P＜0.05).SO and HE staining showed that the endplate morphol-ogy in the modeling day group was similar to the sham group.At 2 weeks post-modeling,changes in carti-laginous endplate morphology and a decrease in porosity were visible.At 4 weeks post-modeling,endplate injury was more pronounced,the cartilaginous endplate protruded towards the disc side,and porosity was es-sentially absent.The annulus fibrosus and nucleus pulposus exhibited degenerative phenotypes:the lamellar structure of the annulus fibrosus was disrupted and disorganized,nucleus pulposus cell numbers were signifi-cantly reduced,and the matrix became fibrotic.Histological scoring revealed significantly increased degenera-tion scores in the 2-week(12.0±0.80)and 4-week post-modeling groups(13.0±1.20)compared to the sham(6.8±0.64)and modeling day groups(6.8±1.36).The intervertebral discs degenerated obviously in the 2-week post-modeling group and 4-week post-modeling group,and statistically significant differences(P＜0.05)were observed between the sham,modeling day,and 4-week post-modeling groups,while no significant differences existed between the other group(P＞0.05).TUNEL staining showed that the percentage of TUNEL-positive cells was(4.43±0.46)％in the sham group,(5.82±0.90)％in the modeling day group,(12.07±1.57)％at 2 weeks post-surgery,and(98.26±4.34)％at 4 weeks post-surgery.Compared to the sham group,both modeling groups showed a reduction in disc cell count and an increased proportion of apoptotic cells(P＜0.05).Conclusions:The modeling method we constructed for rat caudal intervertebral disc cartilaginous endplate injury can cause cartilaginous endplate damage,thereby inducing intervertebral disc degeneration.Its modeling effect is rapid and stable,making it a relatively ideal research model for studying intervertebral disc degeneration induced by endplate injury.
