EFFECTS OF ASTRAGALOSIDE ON CHONDROCYTE PROLIFERATION BY REGULATING THE WNT/Β-CATENIN SIGNALING PATHWAY

Zhuoze Li¹, Bin Zhang^{2, *}

¹School of Medicine, Nanchang University, Nanchang 330006, Jiangxi Province, China - ²Department of Orthopedics, The First Affiliated Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China

Objective: To investigate the effect mechanism of astragaloside on chondrocyte proliferation by regulating the Wnt/β-catenin signaling pathway, and to further elaborate the molecular mechanism of astragaloside in the treatment of osteoarthritis from the molecular biological level. 

Methods: A rabbit OA model was constructed, and chondrocytes were cultured. According to different treatment methods, the cells were divided into a normal control group, an OA model group, 12h low-, medium-, and high-dose astragaloside groups, 24h low-, medium-, and high-dose astragaloside groups, and 48h low-, medium-, and high-dose astragaloside groups. The protein expression of chondrocytes was detected by the western blot assay. The mRNA expression of chondrocytes was measured by the PCR method. The expression of MMP-7, MMP-13, type II collagen carboxy-terminal peptide (CTX-II), Runx2, ADAMTS-4, ADAMTS-5, Wnt2, and β-catenin in the supernatant of human chondrocytes was detected by an ELISA assay. The expression changes of related factors were analyzed to further study the mechanism of astragaloside on chondrocyte proliferation.

Results: Western blotting showed that the β-catenin protein was not expressed in a normal control group. The expression of β-catenin protein in the chondrocyte nucleus of an OA model group was significantly higher than that of the normal control group (P<0.05). After the intervention of astragaloside, the expression of the β-catenin protein in the chondrocyte nucleus of the 12h low-, medium-, and high-dose astragaloside groups had no significant changes compared with that of the pathway activation group. While the expression of β-catenin protein in 12h, 24h and 48h low-, medium-, and high-dose astragaloside groups was lower than that in the pathway activation group, and it was related to the intervention time (P<0.01). The protein expression of β-catenin in the 48h high-dose astragaloside group was dramatically lower than that in the 48h low-dose astragaloside group. The ELISA assay showed that the expression of MMP-7, MMP-13, CTX-II, Runx2, ADAMTS-4, ADAMTS-5, and Wnt2 protein in the supernatant of chondrocytes in the pathway activation group was higher than that in the normal control group (P<0.05) and the astragaloside group (P<0.05). 

Conclusion: Astragaloside can inhibit the Wnt/β-catenin signaling pathway of chondrocytes, reduce the expression of β-catenin, and downregulate the expression of MMP-7, MMP-13, CTX-II, Runx2, ADAMTS-4, ADAMTS-5 and Wnt2. It reveals that the mechanism of astragaloside in the treatment of osteoarthritis may be achieved through inhibiting the Wnt/β-catenin signaling pathway of OA to prevent the degradation of cartilage matrix, inhibit the apoptosis of chondrocytes, and promote the recovery of cartilage function.