低氧预处理通过激活AKT通路提高老年hBM-MSCs对氧化应激损伤的耐受能力

 目的:探讨低氧预处理对老年人骨髓间充质干细胞(hBM-MSCs)的保护作用,为提高老年自体干细胞移植治疗效果提供实验支持。方法:老年hBM-MSCs于低氧培养箱中培养24 h进行低氧预处理,实验分为年轻hBM-MSCs组(young组),老年hBM-MSCs组(old组)及低氧预处理老年hBM-MSCs组(old+hypoxia组)。300 μmol/L H₂O₂作用30 min建立细胞氧化应激模型,50 μmol/L LY294002作用2 h阻断PI3K/AKT信号通路,BrdU掺入实验检测细胞增殖能力; CCK-8法检测细胞活力,Western blot检测凋亡相关蛋白Bax、Bcl-2表达水平和AKT磷酸化水平。结果:BrdU掺入实验显示低氧预处理的老年hBM-MSCs细胞阳性率为39.85%±3.45%,与old组相比增殖能力显著提高(P<0.05)。300 μmol/L H₂O₂作用30 min诱导细胞氧化应激后,old+hypoxia组与old组比较,细胞活力显著提高(P<0.05),凋亡相关蛋白Bax表达量显著降低(P<0.05),抑制凋亡的Bcl-2蛋白表达量显著增高(P<0.05),且AKT磷酸化水平显著增高,差异有统计学显著性(P<0.05);应用LY294002抑制PI3K/AKT信号通路后,细胞活力下降(P<0.05)。结论:低氧预处理可以通过激活AKT信号通路提高老年人骨髓间充质干细胞活力及增殖能力。

Hypoxic preconditioning increases tolerant ability of old human bone marrow mesenchymal stem cells to oxidative stress injury through AKT pathway

AIM: To investigate the protective effect of hypoxic preconditioning on human bone marrow mesenchymal stem cells (hBM-MSCs), and to provide basic experimental support for more effective autologous stem cell transplantation in aged patients. METHODS: The old hBM-MSCs were subjected to hypoxic preconditioning using a hypoxia incubator chamber for 24 h. The cells were divided into young group, old group and old+hypoxia group (with 24 h hypoxic preconditioning). Hydrogen peroxide (H₂O₂, 300 μmol/L) was applied to simulate the oxidative stress. The cells were treated with 50 μmol/L LY294002 for 2 h to inhibit PI3K/AKT pathway. BrdU incorporation and CCK-8 assay were used for analyzing the cell proliferation and viability. The protein levels of Bax, Bcl-2 and p-AKT were measured by Western blot. RESULTS: BrdU-positive cells, which represented the cell proliferation, and the cell viability were significantly increased in old+hypoxia group compared with old group (P<0.05). The protein level of Bax decreased (P<0.05) and Bcl-2 increased (P<0.05) in old+hypoxia group compared with old group after using 300 μmol/L H₂O₂ simulate. the oxidative stress. The phosphorylation of AKT was enhanced by hypoxic preconditioning in old group (P<0.05). The protective effect of hypoxic preconditioning on the cell survival was decreased after treated with LY294002 (inhibitor of the PI3K/AKT pathway) (P<0.05). CONCLUSION: Hypoxic preconditioning increases the survival and proliferation of old hBM-MSCs by activation of AKT pathway.