Abstract:

BACKGROUND: Modic changes, a common observation in MR imaging, are signal intensity changes in vertebral body marrow adjacent to the endplates of degenerative discs. However, degeneration degree of each type of Modic change remains unclearly.
OBJECTIVE: To understand the degree of each type of Modic change degeneration though studying histology and biochemistry composition of Modic change.
METHODS: A total of 36 endplates were harvested during surgery and divided into 3 groups according Modic changes. 12 cases had no Modic changes, 12 cases with type Ⅰ Modic changes, and 12 cases with type Ⅱ Modic changes. Haematoxylin-eosin staining was performed on each group. The histopathologic features of endplates were observed under a light microscope; expression of type Ⅱ collagen was examined by immunohistochemical method, and the content of proteoglycan was determined by phloroglucin way.
RESULTS AND CONCLUSION: Immunohistochemical staining showed that, brown-yellow positive expression could be found in matrix of vertebral endplates in each group. Compared with patients with normal endplates, the integral grey degree of patients with Modic changes were obviously increased (P < 0.05), which greater in Modic Ⅰ than that of Modic Ⅱ (P < 0.05). Proteoglycan determination showed that, vertebral endplates from patients with Modic Ⅰ, or type Ⅱ endplate changes had significantly more proteoglycan combined with patients with normal endplates (P < 0.05). The proteoglycan content in endplates exhibiting Modic Ⅰ were significantly higher than in endplates exhibiting Modic Ⅱ changes (P < 0.05). Histopathologic features were: there were disruption and fissuring in the endplates and vascularized fibrous tissues in Modic Ⅰ, while type Ⅱ changes demonstrated yellow marrow replacement. However, there was no changes in the Modic(-). The results suggest that Modic changes are successive procedure of aggravated degeneration of vertebral endplates.