AIM:To observe the effects of hawthorn leaf polymeric procyanidins ( PPC) on calcium mobiliza-tion of vascular endothelial cells , and to study the underlying mechanism .METHODS: Free calcium in cultured human umbilical vein endothelial cells (HUVECs) was labeled with Fura-2.HUVECs were treated with ATP, a positive control drug, and PPC at concentrations of 12.5, 25 and 50 mg/L..The intracellular calcium concentrations were measured with a living cell microscope for 30 min.RESULTS:PPC concentration-dependently increased the intracellular calcium concen-tration of HUVECs .The intracellular calcium concentrations in 25 and 50 mg/L PPC groups were significantly higher than that in normal group (P<0.01).The dynamic manner of calcium concentration elevations elicited by PPC was a slow in -crease which happened after a latency time of several minutes , lasted for several minutes , and reached a plateau finally . This manner was quite different from that elicited by ATP , a typical SOC operator , hinting different mechanisms between them .Inhibiting the intracellular calcium release did not influence the effects of PPC;however , deleting extracellular calci-um, inhibiting the reverse mode of Na +-Ca2+exchange, or deleting extracellular sodium , restrained or even abolished the effects of PPC.CONCLUSION:PPC elicits calcium mobilization in vascular endothelial cells , which may be one of the mechanisms of the vascular modulatory activity of hawthorn procyanidins .This effect may be achieved through inducing the influx of sodium and then activating the reverse mode of Na +-Ca2+exchange.%目的:探讨山楂叶原花青素多聚体(PPC)对血管内皮细胞钙浓度的影响及其机理,以期阐明其血管活性的机制.方法:体外培养人脐静脉内皮细胞(HUVECs).以Fura-2标记细胞内钙离子,活细胞工作站连续测定细胞内钙离子浓度30 min.结果:12.5~50 mg/L PPC可以浓度依赖地升高HUVECs内钙离子浓度,其作用方式与经典血管内皮细胞钙激动剂ATP明显不同.其中25和50 mg/L的PPC效果与正常组比较,差异有统计学显著性(P<0.01).抑制胞内钙释放,对这一作用没有影响;而去除胞外钙离子、使用钠钙交换体抑制剂以及去除胞外钠离子,均可显著抑制,甚至取消PPC的作用.结论:PPC具有显著的血管内皮细胞钙活化作用,这可能是其调节血管内皮细胞功能的机制之一.这一作用可能是通过促进胞内钠内流,激活钠钙交换体的逆向转运,从而引起胞外钙内流而达到的.
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