骨髓间充质干细胞分泌基质细胞衍生因子1保护心肌细胞

背景：有研究显示表达CXCR4的干细胞能够沿着基质细胞衍生因子1的浓度梯度迁移到心肌梗死部位再生心肌和血管而改善心脏的功能。 目的：探索间充质干细胞通过其分泌的基质细胞衍生因子1对心肌细胞的保护作用。 方法：收集培养2 d的间充质干细胞条件培养基。在缺氧条件，利用基质细胞衍生因子1受体CXCR4阻断剂AMD3100或PI3-K/Akt途径阻断剂LY294002预处理H9C2细胞后，利用AnnexinV/PI双标法流式细胞术分析间充质干细胞条件培养基作用下H9C2细胞凋亡的变化；Western blotting分析H9C2细胞磷酸化Akt蛋白的表达；RT-PCR分析间充质干细胞基质细胞衍生因子1的表达。 结果与结论：RT-PCR结果显示间充质干细胞表达基质细胞衍生因子1，Western blotting结果显示间充质干细胞条件培养基增加了H9C2细胞磷酸化Akt蛋白的水平。AnnexinV/PI分析发现间充质干细胞条件培养基明显降低了H9C2细胞缺氧复氧后的凋亡，且这种抗凋亡作用能被CXCR4阻断剂AMD3100或PI3-K/Akt途径阻断剂LY294002所阻断。说明间充质干细胞通过其分泌的基质细胞衍生因子1通过激活PI3-K/Akt途径保护H9C2细胞，增加H9C2细胞的幸存能力。

Stromal cell-derived factor-1 from bone marrow mesenchymal stem cells protects myocardial cells

BACKGROUND:Several studies have demonstrated that stem cells expressing CXCR4 can migrate into myocardial infarction region to improve the heart function by regenerating myocardial tissue and vessels under the gradient concentrations of stromal cell-derived factor-1. OBJECTIVE:To investigate the protective effect of stromal cell-derived factor-1 from bone marrow mesenchymal stem cells on myocardial cells. METHODS:Conditioned medium of bone marrow mesenchymal stem cells cultured for 2 days was collected. Under hypoxic condition, H9C2 cells were pretreated with CXCR4 inhibitor AMD3100 (5 mg/mL) or PI3-K/Akt inhibitor LY294002 (10 μM) for 1 hour. After treated with bone marrow mesenchymal stem cell conditioned medium, H9C2 cell apoptosis was analyzed by Annexin V/PI double staining methods. Expression of Akt and pAkt in H9C2 cells was analyzed by Western blotting. Expression of stromal cell-derived factor-1 was analyzed by RT-PCR. RESULTS AND CONCLUSION:RT-PCR results showed that bone marrow mesenchymal stem cells expressed stromal cell-derived factor-1. Western blotting results showed that bone marrow mesenchymal stem cell conditioned medium increased pAkt protein level in H9C2 cells. Annexin V/PI analysis showed that bone marrow mesenchymal stem cell conditioned medium significantly decreased apoptosis of H9C2 cells induced by hypoxia/reoxygenation and this anti-apoptotic effect could be blocked by CXCR4 inhibitor AMD3100 or PI3-K/Akt inhibitor LY294002. Stromal cell-derived factor-1 from mesenchymal stem cells plays an important role in the protection of cardiomyocytes through PI3-K/Akt signal pathway.