Secreted modular calcium binding protein regulates autophagy in the acetabular cartilage of rats with developmental dysplasia of the hip

doi:10.12307/2026.681

Abstract

Abstract: BACKGROUND: Developmental dysplasia of the hip is the most common skeletal deformity in children and is an important risk factor for osteoarthritis in young adulthood. Severe cases require hip replacement, which seriously affects the quality of life of patients.
Objective: To investigate the expression of secreted modular calcium-binding protein 2 (SMOC2) in the cartilage acetabular roof of rats with developmental dysplasia of the hip and its effect on chondrocyte autophagy.
Methods: (1) Newborn Sprague-Dawley rats were randomly divided into disease group and control group (normal rats). A developmental dysplasia of the hip model was established in rats of the disease group. At 2 weeks of age, the expression of SMOC2 as well in the cartilage tissues of the acetabular top wall was detected by real-time quantitative polymerase chain reaction and Western blot. Autophagy-related protein expression was assessed via Western blot. (2) Chondrocytes were isolated from rat acetabular tissue and divided into three groups: Sh-NC, Sh-SMOC2-1, and Sh-SMOC2-2 groups. The expression of autophagy related proteins was detected by Western blot, and the number of autophagosomes was observed using a transmission electron microscope. (3) Rat acetabular tissue chondrocytes were extracted, and the cells were divided into three groups: Sh-NC, Sh-SMOC2, and Sh-SMOC2+740 Y-P (phosphatidylinositol 3-kinase activator) groups. The expression of autophagy-related proteins was detected using western blot to investigate whether SMOC2 regulates autophagy-related proteins of chondrocytes through the PI3K/AKT pathway.
Results and Conclusion: (1) Compared with the control group, there was a decrease in the expression of SMOC2, a decrease in the expression of autophagy-associated protein P62, an increase in the expression of Beclin, and no difference in the expression of microtubule-associated protein 1 light chain 3 II/I in cartilage tissues of the rat acetabular top wall in the disease group. (2) Compared with the Sh-NC group, P62 expression was decreased, microtubule-associated protein 1 light chain 3 II/I ratio was increased, and Beclin1 expression was decreased in chondrocytes of the Sh-SMOC2-1 and Sh-SMOC2-2 groups. (3) Compared with the Sh-SMOC2 group, P62 expression was elevated, microtubule-associated protein 1 light chain 3 II/I ratio was decreased, and there was no difference in Beclin1 expression in chondrocytes of the Sh-SMOC2+740 Y-P group. In conclusion, autophagy is enhanced in acetabular chondrocytes of 2-week-old rats with developmental dysplasia of the hip, and SMOC2 can regulate autophagy in rat chondrocytes through the phosphatidylinositol 3-kinase/AKT signaling pathway.

Key words: developmental dysplasia of the hip, SMOC2, autophagy, PI3K/AKT, osteoarthritis, acetabulum, chondrocytes

CLC Number:

Zheng Wen, Zhu Dongsheng, Wang Xiaodong. Secreted modular calcium binding protein regulates autophagy in the acetabular cartilage of rats with developmental dysplasia of the hip[J]. Chinese Journal of Tissue Engineering Research, 2026, 30(18): 4618-4626.

Figures/Tables 7

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