高质量浓度肿瘤坏死因子α对骨髓间充质干细胞的损伤作用

Tumor necrosis factor alpha-induced apoptosis in bone marrow mesenchymal stem cells

BACKGROUND:Stem cell transplantation has achieved good results in the treatment of cerebral ischemia, and how to reduce apoptosis of transplanted cells has become the focus of the therapy.OBJECTIVE:To investigate the injured effect of tumor necrosis factor alpha (TNF-α) on bone marrow mesenchymal stem cells and its mechanism. METHODS:Primary cultured bone marrow mesenchymal stem cells from Sprague-Dawley rats were treated with 200 μg/L TNF-α for 6 hours. Cell vitality was assayed by MTT, and cell apoptosis was observed by Hoechst33342 staining. Apoptotic rate was detected by Annexin-V/PI double staining. Level of oxidative stress was evaluated by determination of malondialdehyde and superoxide dismutase levels. The protein expressions of phosphorylated-Akt, Akt, phosphorylated-FoxO1, FoxO1 were detected by western blot analysis. RESULTS AND CONCLUSION:After treatment with TNF-α, the cell vitality of bone marrow mesenchymal stem cells decreased, the apoptotic rate increased, and the cells were arrested in the S phase. Moreover, the oxidative stress level was elevated, and the protein expression of phosphorylated-Akt and phosphorylated-FoxO1 was significantly reduced compared with the control group (P < 0.05). These results suggest that TNF-α at high level contributes to the S-stage arrest, responsible for the apoptosis processes of bone marrow mesenchymal stem cells via the Akt-FoxO1 pathway.