| Summary: | Objective To investigate the inhibitory effect of curcumin on tumor necrosis factor-α (TNF-α)-induced apoptosis of human umbilical cord mesenchymal stem cells (hUC-MSCs) and explore the underlying mechanism. Methods hUC-MSCs cultured in vitro were treated with 5 ng/mL TNF-α and different concentrations of curcumin. LDH release assay and flow cytometry were used to assess the inhibitory effect of curcumin against TNF-α-induced cell apoptosis. Western blotting was used to detect the expression of the apoptosis-related molecules in the downstream MAPK signaling pathway (ERK, JNK, and p38) of tumor necrosis factor receptor (TNFR) and the apoptosis-related proteins (Bcl-2 and Bax). Results LDH release assay showed that TNF-α at a concentration above 5 ng/mL induced obvious apoptosis in cultured hUC-MSCs. Curcumin at the concentrations between 0.5 and 4 μmol/L significantly inhibited TNF-α-induced hUC-MSC apoptosis in a concentration-dependent manner; Flow cytometry also confirmed that 4 μmol/L curcumin significantly inhibited TNF-α-induced apoptosis of hUC-MSCs (P < 0.05). The results of Western blotting showed that curcumin treatment caused ERK activation and enhanced the expression of Bcl-2 to increase the Bcl-2/Bax ratio (P < 0.05) without obviously affecting the expression of JNK and p38 proteins in the cells. Conclusion Curcumin can inhibit TNF-α-induced apoptosis of hUC-MSCs possibly by activating ERK signaling pathway and enhancing Bcl-2 expression.
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