Microtia patients: Auricular chondrocyte ECM is promoted by CGF through IGF-1 activation of the IGF-1R/PI3K/AKT pathway.

OBJECTIVE

To explore the effectiveness of the insulin-like growth factor 1 receptor (IGF-1R)/PI3K/AKT pathway in promoting the synthesis of the auricular chondrocyte extracellular matrix (ECM) using concentrated growth factor (CGF).

METHODS

Chondrocytes isolated from the remnant auricular cartilage of microtia patients were randomly divided into different experimental and control groups, then stimulated with a reagent. IGF-1 released by CGF was quantified by enzyme-linked immunosorbent assay. Glycosaminoglycan (GAG), proteoglycan, and type II collagen (COLAII) were examined by histological and immunohistological analysis. Expression levels of IGF-1R, pIGF-1R, PI3K, pPI3K, AKT, pAKT, COLAII, and Aggrecan were detected by western blot analysis technique and gene expression was tested by real-time polymerase chain reaction.

RESULTS

CGF significantly stimulated the synthesis of COLAII and Aggrecan and increased the phosphorylation levels of IGF-1R, PI3K, and AKT. Small interfering RNA IGF-1 blocked ECM synthesis, COLAII and Aggrecan gene expression, and IGF-1R/PI3K/AKT activation. Inhibitor AG1024 and LY294002 significantly inhibited ECM synthesis and the phosphorylation of IGF-1R, PI3K, and AKT.

CONCLUSION

CGF-released IGF-1 stimulates the synthesis of the auricular chondrocyte ECM via the IGF-1R/PI3K/AKT signaling pathway.