Role of Matrix Metalloproteinases in Degenerative Lumbar Disc; Molecular and Immunohistochemical Study

Objective : Little is known about the comprehensive molecular and biological mechanism on the development of the degeneration of the intervertebral disc. Many kinds of matrix metalloproteinase[MMP] initiate the degradation of the extracellular matrix including several kinds of collagens and proteoglycans. We compared molecular and immunohistochemical features of degenerated intervertebral disc and normal counterparts in order to investigate the role of MMP-1, 2, 3, 9. Methods : We have evaluated MMP-1, 2, 3, 9 expression in 30 surgically resected lumbar disc from degenerative disc disease patients and 5 normal control cases. RT-PCR[reverse transcriptase-polymerase chain reaction] and immunohistochemistry were performed. Results : By RT-PCR, normal tissue samples showed merely scant expression of MMP-1, 2, 3, 9 mRNA, but degenerated disc samples revealed more pronounced expression. mRNA amplifications were detected in 60%, 63.3%, 70%, 53.3% cases By immunohistochemistry, normal tissue samples showed minimal protein expression of MMP-1, 2, 3, 9, but degenerated disc samples revealed more pronounced expression. Protein expressions were detected in 73.3%, 63.3%, 76.7%, 63.3% cases. Both the mRNA amplification and protein overexpression rates were significantly higher in degenerated disc than in the normal tissue. Concordance between both the mRNA amplification and protein expressions of MMP-1, 3, 9 were not observed, but there is well correlation in MMP-2 expression. Conclusion : We concluded that the over-expressions of the MMP-1, 2, 3, 9 may contribute to the development of degeneration of the intervertebral disc.