OBJECTIVESTo investigate the expression of chondromodulin-1 (ChM-I) in human adult degenerative intervertebral disc (IVD) cells and the relationship between ChM-I expression and disc degeneration.

METHODSThree degenerated disc specimens obtained from patients in the treatment of disc degenerative disease from March to April 2009 were used for cell culture. ChM-I expression in IVD cells was examined by RT-PCR and Western blot. The effect of basic fibroblast growth factor (bFGF) on the expression of ChM-I was assessed by real-time PCR and Western blot. From October 2008 to October 2009, 26 human IVD tissues were obtained from patients in the surgical treatment of disc degenerative disease at different stage of degeneration according to MRI. Six IVD tissues removed from patients with metastatic spinal tumor were used as normal control. The expression of ChM-I determined by immunohistochemical analysis was correlated with MRI degeneration grade.

RESULTSRT-PCR and Western blot examination showed that ChM-I was expressed in both adult degenerative anulus fibrosus and nucleus pulposus cells. The mRNA and protein expression of ChM-I were both down-regulated by administration of bFGF with dose-dependent way (P < 0.05). Immunohistochemical analysis showed the percent of ChM-I immunopositive cells in the control group was 0.12 ± 0.03, and the number increased significantly in the advanced degeneration group (P < 0.05).

CONCLUSIONSThe current results demonstrate that IVD cells express ChM-I. Administration of bFGF down-regulates the expression of ChM-I. The expression of ChM-I is correlated with the degree of IVD degeneration which means it may involve in the process of IVD degeneration.