SEQUENTIAL DYNAMICS OF MONOCYTE CHEMOTACTIC PROTEIN-1 EXPRESSION IN HERNIATED NUCLEUS PULPOSUS RESORPTION

We previously demonstrated that the granulation tissues of herniated n ucleus pulposus are composed of a marked infiltration of macrophages t hat strongly express monocyte chemotactic protein-1. Monocyte chemotac tic protein-1 is a chemotactic cytokine that contributes to the activa tion and recruitment of macrophages. Relatively little is known about its role in the resorption process of herniated nucleus pulposus. To c larify the sequential dynamics of expression of monocyte chemotactic p rotein-1 in the granulation tissues of herniated nucleus pulposus, we introduced a rat autologous transplantation model of nuclear materials onto its lumbar dura mater and performed immunohistological analysis and competitive polymerase chain reaction assay using the grafted samp les. Immunohistological analysis demonstrated that the majority of inf iltrating mononuclear cells expressed monocyte chemotactic protein-1, Monocyte chemotactic protein-1 mRNA was expressed in the first 3 weeks after the procedure and was significantly and maximally upregulated a t 1 week, To determine whether human recombinant monocyte chemotactic protein-1 facilitates the resorption process of herniated nucleus pulp osus, we introduced another model of autologous transplantation, where in the nuclear materials were grafted to the abdominal subcutaneous ti ssues and recombinant monocyte chemotactic protein-1 was subsequently applied to these materials, When monocyte chemotactic protein-1 was in jected into the murine nucleus pulposus tissues, they reduced in size more rapidly than in the control group. These findings suggest that mo nocyte chemotactic protein-1 plays all important rule in the recruitme nt of macrophages in the early phase of the resorption process of hern iated nucleus pulposus and that its application may physiologically fa cilitate the resorption process of the nucleus pulposus.