Objective: To explore the expression and significance of Wnt/β-catenin signaling pathway in the natural degeneration of endplate chondrocytes in rats.
Methods: Endplate chondrocytes extracted from lumbar vertebrae were divided into control (P2 cell), naturally passaged (P5 cell) and wnt signaling pathway inhibition groups. The morphology of endplate chondrocytes was observed by inverted microscope. Hematoxylin and eosin (HE) and toluidine blue stains were used to identify their phenotypes. Type II collagen marker, SOX-9 and aggrecan genes were detected by reverse transcription-polymerase chain reaction (RT-PCR) to verify the degeneration model. Based on this model, the changes of β-catenin were detected by RT-PCR and Western blot. Laser confocal microscopy was used to detect the expression and localization of β-catenin within endplate chondrocytes.
Results: With natural passaging, endplate cartilage cells appeared spindle-shaped and gradually lost chondrocytic phenotypes. The levels of type II collagen (P5/P2 = 0.11, P = 0.003 9), SOX-9 (P5/P2 = 0.58, P = 0.016 8) and aggrecan (P5/P2 = 0.32, P = 0.004 6) significantly reduced; β-catenin (P5/P2 = 1.62, P = 0.008 2) significantly increased. β-catenin was down-regulated (XAV-939/P5 = 0.23, P = 0.001 7) in inhibition group. And type II collagen (XAV-939/P5 = 2.60, P = 0.018 0), SOX-9 (XAV-939/P5 = 1.47, P = 0.038 2) and aggrecan (XAV-939/P5 = 2.56, P = 0.004 1) significantly increased. β-catenin had a higher expression and obviously entered into nuclear transcription in P5 generation and decreased in inhibition group.
Conclusion: β-catenin plays an important role in the in vitro degeneration of endplate chondrocytes. There are great potentials for protecting endplate cartilage degeneration by regulating the Wnt/β-catenin signaling pathway.