Expression of matrix metalloproteinases is positively related to the severity of disc degeneration and growing age in the East Asian lumbar disc herniation patients.

Matrix metalloproteinases (MMPs) have been known to play a pivotal role in the age- and/or disease-related degradation of intervertebral discs. We aimed to explore as to whether the expression of these enzymes is correlated to disc degeneration caused by increasing age and severity of herniation in the East Asian population. Thus, we studied the expressions of MMP-1 (collagenase), MMP-2 (gelatinase) and MMP-14 (membrane-type protease) in 65 patients diagnosed with lumbar disc herniation. The patients were divided into 3 groups according to their age, and the severity of herniation was graded on the basis of magnetic resonance imaging (MRI). Immunohistochemistry analysis was conducted to determine the expression of different MMPs in the post-surgery disc specimens. The results showed that expressions of these three enzymes were directly and positively related to the degree of disc degradation. Whereas, the MMP-1 expression was found to be elevated with the increasing age, the MMP-2 and MMP-14 remained unchanged in groups of different ages. A direct correlation between the expressions of MMP-2 and MMP-14 suggested a role of MMP-14 in the modulation of MMP-2 expression.