BACKGROUND:Stem cel transplantation has achieved good results in the treatment of cerebral ischemia, and how to reduce apoptosis of transplanted cel s 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 cel s and its mechanism.
METHODS:Primary cultured bone marrow mesenchymal stem cel s from Sprague-Dawley rats were treated with 200μg/L TNF-αfor 6 hours. Cel vitality was assayed by MTT, and cel 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 cel vitality of bone marrow mesenchymal stem cel s decreased, the apoptotic rate increased, and the cel s 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-αat high level contributes to the S-stage arrest, responsible for the apoptosis processes of bone marrow mesenchymal stem cel s via the Akt-FoxO1 pathway.

According to teaching practice,the authors discuss the problems on teaching exploratory experiment of experimental physiology sciences and propose some reflection and suggestions.