内皮祖细胞分泌SDF-1及其抗内皮祖细胞凋亡作用

Endothelial progenitor cells secrete SDF-1 and SDF-1 protects endothelial progenitor cells from apoptosis

目的探讨内皮祖细胞(EPC)能否分泌基质细胞衍生因子-1(SDF-1),及SDF-1能否抑制紫杉醇、AMD3100(特异性阻断SDF-1与其受体CXCR4结合)等诱导的EPC凋亡。方法取不同时间段的EPC培养液上清,采用ELISA检测上清中SDF-1a浓度。用不同浓度的紫杉醇、AMD3100及无血清培养诱导EPC凋亡;或在上述基础上加不同浓度的SDF-1a处理;48 h后采用TUNEL法和流式细胞仪检测各组EPC凋亡率。结果EPC培养液上清中SDF-1a浓度显著高于对照组(P<0.01)。紫杉醇、AMD3100和无血清培养一样,均可显著增高EPC凋亡率(P<0.01);加入外源性SDF-1a可显著降低紫杉醇组、无血清培养组EPC凋亡率(P<0.01),却不能降低AMD3100组EPC凋亡率。结论体外培养的EPC可分泌SDF-1a,采用AMD3100阻断其作用可诱导EPC凋亡;SDF-1a可对抗紫杉醇和无血清培养诱导的EPC凋亡,但对AMD3100诱导的凋亡无效。

AIM To investigate whether endothelial progenitor cells （EPC） can secrete stromal cell-derived factor-1 （ SDF-1 ） and whether SDF-1 can inhibit paclitaxel, AMD3100 and serum starvation-induced apoptosis in EPC. METHODS SDF-1 in cell culture supernates was determined by enzyme-linked immunosorbent assay. To induce apoptosis, EPC in 96 or 24-well plates were replaced with media containing different concentrations of paclitaxel, AMD3100 （an antagonist of CXCR4）or serum absent media and were incubated for 48 h. Or under the above conditions, the medium was supplemented with different concentrations of SDF-1. After 48 h incubation, apoptosis was determined by TUNEL method and flow cytometry. RESULTS SDF-1 concentration in cell culture supernates was higher than that in endothelial basal medium（P 〈0.01 ）. Paclitaxel, AMD3100 and serum starvation all increased apoptosis in both EPC and control（P 〈0.01 ）. SDF-1 reduced apoptosis induced by paclitaxel or serum starvation in EPC （P 〈0.01 ）, but not reduce AMD3100-induced EPC apoptosis. CONCLUSION In vitro, EPC secretes SDF-1 and blocking its effect by AMD3100 induces EPC apoptosis. SDF-1 protects EPC from paclitaxel or serum starvation-induced apoptosis, but not from AMD3100-induced apoptosis.