Analyses of Ca^<2+> signaling mechanisms of vascular and nerve formation using Ca^<2+> transporter-deficient mice

Na~+/Ca~(2+)交换器-1(NCX1)被认为与内皮性一氧化氮(NO)的产生有关。在这项研究中，我们利用杂合的NCX1基因敲除(NCX1^&lt；+/-&gt；)小鼠，研究了NCX1在急性后肢缺血血管生成反应中的作用。此外，由于脂微球包裹前列腺素E_1(Lipo-PGE_1)是公认的治疗外周动脉疾病的有效药物，因此我们研究了Lipo-PGE_1在后肢缺血诱导血管生成中的作用。手术诱导大鼠一侧后肢缺血，激光多普勒监测血流恢复情况，连续4周。脂微球-前列腺素E_1治疗可促进野生型小鼠血流恢复和毛细血管密度。第28天的Western blotting显示，Lipo-PGE1可增加缺血肌肉中VEGF和磷酸化Akt的表达水平。有趣的是，与野生型小鼠相比，NCX^&lt；+/-&gt；小鼠的血流恢复显著增强，尽管LipoPGE1治疗也同样增强了这种恢复。此外，为了研究内皮型一氧化氮合酶的可能参与，我们用N^G-硝基-L-精氨酸甲酯(L-NAME)对小鼠后肢缺血进行了研究。L-NAME治疗消除了在NCX1；+/-&GT；和Lipo-PGE1治疗的小鼠中观察到的增强的血流恢复。这些结果表明，NCX1和Lipo-PGE1参与了内皮一氧化氮合酶依赖的血管生成。

The Na^+/Ca^2+ exchanger type-1 (NCX1) is considered to be involved in endothelial nitric oxide (NO) production. In this study, we examined the role of NCX1 in angiogenic response to acute hindlimb ischemia by using heterozygous NCX1 knockout (NCX1^<+/->) mice. Furthermore, since Lipo-PGE1 (prostaglandin El encapsulated into lipid microsphere) is well known as a useful drug for peripheral arterial disease, we examined the effect of Lipo-PGE1 in hindlimb ischemia-induced angiogenesis. We surgically induced unilateral hindlimb ischemia and monitored the blood flow recovery by Laser Doppler imaging for 4 weeks. Lipo-PGE1 treatment enhanced the blood flow recovery and capillary density in wild-type mice. Western blotting at 28 day showed that Lipo-PGE1 increased VEGF and phospho-Akt expression levels in the ischemic muscles. Interestingly, the blood flow recovery in NCX^<+/-> mice was significantly augmented compared with that in wild-type mice, although it was similarly enhanced by Lipo-PGE1 treatment. Moreover, to study possible involvement of endothelial NO synthase, we administered N^G-nitro-L-arginine methyl ester (L-NAME) to mice with hindlimb ischemia. L-NAME treatment eliminated the enhanced blood flow recovery observed in both NCX1^<+/-> mice and Lipo-PGE1-treated mice. These results suggest that NCX1, as well as Lipo-PGE1, is involved in endothelial NO synthase-dependent angiogenesis.