Activation and localization of cartilage-derived morphogenetic protein-1 at the site of ossification of the ligamentum flavum

Localization and expression of cartilage-derived morphogenetic protein (CDM P)-1 in tissues at the site of ossification of the ligamentum flavum (OLF) were examined by immunohistochemistry and in situ hybridization. The CDMP-1 protein and messenger ribonucleic acid (mRNA) were localized in spindle-sh aped cells and chondrocytes in the OLF tissues. CDMP-1 was not detected in cells in non-ossified sites. These data indicate that CDMP-1 is locally act ivated and localized in spindle-shaped cells and chondrocytes at the site o f OLF. Given the previously reported promoting action of CDMP-1 for chondro genesis, the current results suggest that CDMP-1 may be involved in the pro gression of OLF, leading to the narrowing of spinal canal and thus causing severe clinical manifestations.