Expression of AMP-activated protein kinase in subcultured rat endplate chondrocytes / 中国组织工程研究

ABSTRACT

BACKGROUND:Endplate cartilage degeneration initiates intervertebral disc degeneration. AMP-activated protein kinase (AMPK) regulates the formation and degradation of cartilage. OBJECTIVE:To explore the role of AMPK in an in vitro natural degeneration model of chondrocytes derived from endplate of rat intervertebral discs. METHODS:Morphology of in vitro subcultured endplate chondrocytes of rat intervertebral discs at passages 0, 2, and 5 were observed under an inverted microscope fol owing cytoskeleton staining. Chondrocyte phenotype, proliferation, and the cartilage marker genes (type II col agen, proteoglycan, SOX-9, matrix metal oproteinase-3 and-13), and AMPK phosphorylation were determined by toluidine blue staining, MTT assay, real-time PCR analysis, and western blot assay, respectively. RESULTS AND CONCLUSION:The altered morphology, decreased proliferation ability, and phenotype loss were observed in chondrocytes with increased passage number. Gene expression of type II col agen, proteoglycan, SOX-9 was significantly decreased;while gene expression of matrix metal oproteinase-3 and-13 was significantly increased in endplate chondrocytes at passage 5 compared with those at passages 0 and 2. AMPK phosphorylation in endplate chondrocytes at passage 5 was significantly decreased. These findings indicate that AMPK phosphorylation is involved in in vitro natural degeneration of chondrocytes derived from the endplate of rat intervertebral discs, and the degeneration of endplate chondrocytes and intervertebral discs can be inhibited through the regulation of AMPK activity.