bFGF诱导血管形成中Mg^(2+)重要作用的研究

Evidence for a major role of Mg^(2+) in bFGF-mediated angiogenesis

目的探讨碱性成纤维细胞生长因子(basic fibroblastgrowth factor,bFGF)对人脐带静脉内皮细胞(human umbilicalvein endothelial cells,HUVECs)内游离镁离子浓度([Mg2+]i)的调节机制及Mg2+与新生血管形成间相关性。方法我们采用荧光指示剂mag-fura-2,运用PTi阳离子测定系统动态测HUVECs的[Mg2+]i。新鲜脐带内灌注胶原酶消化,获得内皮细胞,用含体积分数为0.2胎牛血清的M199液进行培养,当细胞外Mg2+浓度分别为0,1和2mmol.L-1时,观察了bFGF促进HUVECs血管形成的能力。结果bFGF诱导的[Mg2+]i增加与细胞外Mg2+存在无关,在细胞外无Mg2+时,bFGF能剂量依赖性地增加[Mg2+]i。bF-GF诱导的[Mg2+]i增加与细胞外Na+浓度和细胞内Ca2+浓度无关,经bFGF的受体(KDR)阻断剂SU1498预处理,能明显阻断bFGF诱导的[Mg2+]i增加。当细胞外Mg2+为0mmol.L-1时,HUVECs形成血管作用受到明显抑制,bFGF也不刺激血管形成,但当细胞外Mg2+为1或2mmol·L-1时,bFGF可促进HUVECs形成血管。当细胞外Mg2+为1mmol·L-1时,KDR阻断剂SU1498可明显抑制bFGF促进HUVECs形成血管的作用。结论bFGF通过KDR信号传递途径使细胞内的Mg2+库释放Mg2+,从而增加HUVECs的[Mg2+]i,并对促进血管形成起重要作用。

Aim The mechanism of basic fibroblast growth factor（bFGF） in mediating increase of intracellular free magnesium （ [ Mg^2＋ ] i ） in human umbilical between Mg^2＋ and angiogenesis were investigated in this study. Methods The change of[ Mg^2＋ ]i in HUECs were quantitatively detected in intracellular cation measurement system via loaded with the fluorescent magnesium indicator mag-fura-2. Endothelial cells were primarily acquired by infusion of collagen enzyme solutioninto the lumens of human umbilical veins and cultured in M199 with 0. 2 fetal bovine serum. The role of bFGF in angiogenesis was observed in presence of 0, Mg^2＋ 1 mmol·L^-1 or 2 mmol·L^-1 of extracellular. Results bFGF dose-dependently increased [ Mg^2＋ ] i, and there was not any significant difference among the groups of 0,1 mmol·L^-1 and 2 mmol·L^-1of extracellular Mg^2＋ ; similar results were obtained in groups done with Na^＋ and Ca^2＋. Pretreatment with bFGF receptor-2 （KDR） inhibitor （ SU1498 ） blocked the increase of [ Mg^2＋]i induced by bFGF. Unlike in the group of 0mmol·L^-1 extracellular Mg^2＋ , the apparent angiogeneses were observed in the groups of 1mmol·L^-1 and 2 mmol·L^-1 extracellular Mg^2＋ in the presence of bFGF. bFGF-induced angiogenesis was significantly blocked with SU1498 in the presence of 1mmol·L^-1 extracelluar Mg^2＋. Conclusions These results suggest that the increase of [ Mg^2＋ ]i by bFGF come from intracellular Mg^2＋ pools mediated by KDR- dependent signaling pathways, thereby resulting in the bFGF-induced angiogenesis.