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2022, Vol. 26 ›› Issue (14): 2161-2166Regulatory role of curcumin in hydrogen peroxide-induced autophagy in chondrocytesCao Shuxing1, Song Yongzhou1, Li Ming1, Zhang Hongliang1, Zhao Lihui2, Ma Wei1
Abstract: BACKGROUND: Curcumin has a good therapeutic effect on osteoarthritis, but the specific mechanism is still unclear. Activation of autophagy can reduce the severity of osteoarthritis. OBJECTIVE: To investigate the regulatory effect of curcumin on hydrogen peroxide (H2O2)-induced autophagy in chondrocytes. METHODS: C57 mouse articular chondrocytes were cultured in vitro and randomly divided into control group, model group (treated with H2O2) and curcumin low-, medium- and high-dose groups (10, 20, 40, 80 μmol/L). Model group was treated with H2O2 (1 mmol/L) to simulate oxidative stress in osteoarthritis. In the different curcumin groups, chondrocytes were treated with different concentrations of curcumin for 48 hours, followed by addition of H2O2. Twenty-four hours later, the cells were collected for detection. Cell counting kit-8 assay was used to detect cell viability in each group. Interleukin-6 and tumor necrosis factor-α levels were detected by ELISA. TUNEL staining was used to detect cell apoptosis. The apoptosis rate of each group was detected by flow cytometry. The expression levels of cleaved caspase-3, Bax/Bcl2, Beclin1, LC3-II/I, protein kinase B (Akt) and mammalian target of rapamycin (mTOR) were detected by western blot. The expression of cartilage matrix degradation related genes, including matrix metalloproteinase 13, ADAM metallopeptidase with thrombospondin type 1 motif 5, type II collagen α1, and Aggrecan, were detected by qRT-PCR. RESULTS AND CONCLUSION: Compared with the model group, the activity of chondrocytes was significantly increased after curcumin intervention (P < 0.05). The expression of inflammatory cytokines was significantly decreased (P < 0.05). Apoptosis was significantly decreased (P < 0.05). Apoptosis-related markers, cleaved caspase-3 and Bax/Bcl2 ratio, were significantly decreased (P < 0.05). The expression of autophagy-related markers, LC3-I/II and Beclin1, was significantly increased (P < 0.05). The expression levels of Akt and mTOR were significantly decreased (P < 0.05). qRT-PCR showed that the mRNA expressions of matrix metalloproteinase 13 and ADAM metallopeptidase with thrombospondin type 1 motif 5 were decreased, while the expressions of type II collagen α1 and Aggrecan were increased (P < 0.05). It is suggested that curcumin can reduce the H2O2-induced apoptosis in chondrocytes by promoting autophagy, and this effect may be related to the Akt/mTOR signaling pathway. Key words: curcumin, osteoarthritis, chondrocyte, autophagy, hydrogen peroxide |