Compressive stress induces degeneration of cartilaginous endplate cells through the SOST/Wnt/beta-catenin pathway

Xiang Pan; Che Yanjun; Luo Zongping

doi:10.12307/2025.277

Abstract：BACKGROUND:Many factors can cause disc degeneration,including aging,nutritional deficiency,and mechanical factors.The mechanical load is considered to be a very important factor,but its mechanism is still unclear. OBJECTIVE:To investigate the role of sclerostin(SOST)and Wnt/β-catenin signaling pathways in inducing degeneration of endplate cartilage. METHODS:Cartilage endplate cells were extracted from 4-week-old male Sprague-Dawley rats.Compressive stress was applied to endplate chondrocytes in vitro using a mechanical loading apparatus,and the cell viability was determined by the cell counting kit-8 assay at 1,3,5,and 7 days after compression.Western blot,reverse transcription quantitative PCR,and cellular immunofluorescence techniques were employed to examine intracellular cartilage markers(Aggrecan and type Ⅱ collagen)as well as calcification-related factors(Runx2 and osteocalcin).The expression of extracellular matrix degradation enzyme and genes related to the signaling pathway(SOST and β-catenin)was also analyzed. RESULTS AND CONCLUSION:Under compressive stress,the cell activity of endplate chondrocytes increased with both the duration and intensity of stress.Furthermore,the expression levels of Aggrecan and type Ⅱ collagen decreased in endplate cells under compressive stress,while those of calcification-related factors(Runx2 and osteocalcin)increased.Additionally,compressive stress promoted extracellular matrix degradation in endplate chondrocytes,leading to an increase in matrix metalloproteinase 3 and matrix metalloproteinase 13 expression.Abnormalities were observed in the Wnt/β-catenin signaling pathway within these cells under compressive stress,characterized by a decrease in specific inhibitory factor SOST expression accompanied by abnormal accumulation of β-catenin.To conclude,decreased SOST expression in endplate chondrocytes under compressive stress activates the Wnt/β-catenin signaling pathway,thereby promoting calcification,degeneration and extracellular matrix degradation in the cartilage endplate.