Expression of lipid metabolism and cartilage degeneration-related factors in lumbar vertebral endplate Modic changes

Abstract

Objectives: This study aims to investigate the relationship between the expression of lipid metabolism and cartilage degeneration-related factors and Modic changes (MCs) of lumbar vertebral.

Patients and methods: This prospective study included a total of 10 patients (6 males, 4 females; mean age: 60.4±8.7 years; range 51 to 82 years) who underwent lumbar interbody fusion surgery due to degenerative lumbar diseases (MC group), and 10 control patients (4 males, 6 females; mean age: 49.7±9.8 years; range, 42 to 76 years) with lumbar burst fractures (nonMC group) between January 2020 and December 2022. Clinical imaging data and cartilage tissues were collected to observe cartilage characteristics and pathological changes. The relative expression levels of lipid metabolism-related inflammatory factors matrix metalloproteinase-1 (MMP-1), a disintegrin and metalloproteinase with thromboSpondin motifs-5 (ADAMTS-5), and aggrecan in cartilage were detected by quantitative polymerase chain reaction (qPCR). The relative expression levels of MMP-1 and ADAMTS-5 proteins in cartilage tissues were detected by Western blotting.

Results: There were no significant differences in the baseline characteristics between the two groups. The color and transparency of the endplate cartilage in the control group were significantly better than those in the MCs group. Radiographic and hematoxylin-eosin staining of the endplate cartilage tissues showed that the extracellular matrix was higher in the control group than in the MCs group (p<0.05). Compared to the control group, qPCR analysis showed higher expression of MMP-1 and ADAMTS-5 in the MCs group, while aggrecan expression was lower (p<0.05). Western blot analysis showed that both MMP-1 and ADAMTS-5 expression were higher in the MCs group than in the control group (p<0.05).

Conclusion: Lipid metabolism and cartilage degeneration-related inflammatory factors exist in the vertebral endplate of the patients with degenerative lumbar diseases, and the upregulation of MMP-1 and ADAMTS-5 may be related to MCs and endplate degeneration.

Figure 1. (a, b) Cartilage macroscopic photos of non-MCs and MCs groups. (c, d) CT image of non-MCs patient and MRI image of MCs patient. Red arrows indicate sites of fracture and disc Modic changes. (e, f) 50× HE staining of the cartilage tissue. (g, h) 100× HE staining of the cartilage tissue. The non-MC group had a higher extracellular matrix than the MC group. The non-MC group had a homogeneous extracellular matrix and small round chondrocytes, whereas the MC group showed a fibrotic and sclerotic extracellular matrix with fewer chondrocytes.: MCs: Modic changes; CT: Computed tomography.

Figure 2. Changes in metabolism-related factors. (a) qPCR results; (b) Representative Western blot bands; (c) Statistical analysis of Western blot results.: qPCR: Quantitative polymerase chain reaction; ADAMTS-5: A disintegrin and metalloproteinase with thromboSpondin motifs-5; MMP-1: Matrix metalloproteinase-1; MCs: Modic changes.