Department for Experimental Therapeutics, Institute of Pharmacology and Toxicology, Academy of Medical Science, 14 Eugene Pottier Str., 03057, Kiev, Ukraine.
J Physiol Sci. 2010 Mar;60(2):161-72. doi: 10.1007/s12576-009-0080-4. Epub 2010 Jan 7.
The effect of intravenous administration of human mesenchymal stromal stem cells (hMSC) has been evaluated by means of large-conductance calcium-dependent potassium channel (BK(Ca)) activity measurements in thoracic aorta smooth muscle cells (SMC) obtained from non-fatal whole-body irradiated rats, using the patch clamp technique in whole-cell modification, and the standard acetylcholine (ACh) test to evaluate functional endothelium integrity using SM contractile recordings. Myofilament calcium sensitivity was estimated using simultaneous contractile recordings versus Ca(2+). Arterial blood was measured in intact and irradiated rats before and after hMSC administration. Stimulation of isolated SMC from the control group of animals with depolarizing voltage steps showed that outward K(+) currents sensitive to the BK(Ca) inhibitor paxilline were expressed. Outward currents in SMC obtained from irradiated animals were significantly reduced on the 30th day of post-irradiation. Irradiation led to a significant elevation in arterial blood pressure and reduced ACh-induced relaxation responses in irradiated rats as compared with the control group. Simultaneous measurements of contractile force and Ca(2+) showed that myofilament Ca(2+) sensitivity had increased following irradiation. Intravenously injected hMSC effectively restored BK(Ca) current and the amplitude of ACh-induced endothelium-dependent vasodilatation in vascular tissues obtained from post-irradiated rats. SMC obtained from irradiated rats treated with hMSC demonstrated a significantly increased paxilline-sensitive component of outward potassium currents, indicating that BK(Ca) activity had been restored. hMSC administration normalized increased blood pressure and myofilament Ca(2+) sensitivity in irradiated animals. When administered to healthy rats, hMSC were without effects on either of these. This study does not provide any immunohistochemical proof of hMSC engraftment in the host rats. PCR analysis showed that hMSCs were negative for hematopoietic cell markers and positive for hMSC markers. There were no clinical signs of graft-versus-host disease throughout the experimental period of 30 days. The data obtained suggest that hMSC demonstrate a clearly expressed ability to normalize vascular function damaged following irradiation, i.e. to reduce an elevated arterial blood pressure and myofilament Ca(2+) sensitivity, and to repair BK(Ca) function and endothelium-dependent relaxation in vascular tissues obtained from irradiated animals. Thus, hMSC seem to be worthwhile therapeutic approach in cases of ionizing irradiation accident or radiation beam therapy.
静脉注射人间质基质干细胞（hMSC）对非致死性全身辐射大鼠胸主动脉平滑肌细胞（SMC）的大电导钙依赖性钾通道（BK（Ca））活性进行了评估，使用全细胞膜片钳技术的全细胞修饰，以及标准乙酰胆碱（ACh）测试，通过 SM 收缩记录来评估功能内皮完整性。使用同步收缩记录与[Ca（2+）]（i）评估肌丝钙敏感性。在 hMSC 给药前后测量完整和辐射大鼠的动脉血。刺激对照组动物的分离 SMC 用去极化电压步长显示表达对 BK（Ca）抑制剂巴氯芬敏感的外向 K（+）电流。在辐射后第 30 天，从辐射动物获得的外向电流明显减少。与对照组相比，辐射导致动脉血压升高和 ACh 诱导的辐射大鼠松弛反应减少。同时测量收缩力和[Ca（2+）]（i）表明，肌丝钙敏感性在照射后增加。静脉注射 hMSC 有效恢复了从辐射后大鼠获得的血管组织中的 BK（Ca）电流和 ACh 诱导的内皮依赖性血管舒张的幅度。用 hMSC 处理的来自辐射大鼠的 SMC 显示出显著增加的巴氯芬敏感外向钾电流成分，表明 BK（Ca）活性已恢复。hMSC 给药使辐射动物的血压和肌丝钙敏感性正常化。当给予健康大鼠时，hMSC 对这两者均无影响。本研究未提供任何 hMSC 移植到宿主大鼠中的免疫组织化学证据。PCR 分析显示 hMSC 对造血细胞标志物呈阴性，对 hMSC 标志物呈阳性。在整个 30 天的实验期间，没有移植物抗宿主病的临床迹象。获得的数据表明，hMSC 表现出明显表达的能力，可使照射后受损的血管功能正常化，即降低升高的动脉血压和肌丝钙敏感性，并修复 BK（Ca）功能和来自辐射动物的血管组织中的内皮依赖性舒张。因此，hMSC 似乎是电离辐射事故或辐射束治疗的有价值的治疗方法。
