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目的探讨虎杖苷（ＰＤ）改善休克动物微循环的作用机制。方法股动脉放血复制休克模型，取肠系膜微动脉用链霉蛋白酶Ｅ消化以分离单个血管平滑肌细胞（ＶＳＭＣ），再用不同荧光染料分别标记细胞，在激光共聚焦显微镜上测定细胞内钙（［Ｃａ２＋］ｉ）、ｐＨ和膜电位的变化。结果ＰＤ（０４ｍｍｏｌ·Ｌ－１）使休克大鼠ＶＳＭＣ［Ｃａ２＋］ｉ浓度在１０ｍｉｎ内显著下降至加药前的７８４％±５６％、ｐＨ下降至原来的７２８％±８２％；而正常对照组ＶＳＭＣ［Ｃａ２＋］ｉ升高１７５％±６３％、ｐＨ上升３４％±１０１％。当ＰＤ加入前１０ｍｉｎ用钙通道阻断剂维拉帕米（５０μｍｏｌ·Ｌ－１）预处理后，则动物不论休克与否，其［Ｃａ２＋］ｉ、ｐＨ都显著下降。另外ＰＤ使正常及休克大鼠ＶＳＭＣ膜电位负值下降，出现去极化反应。加入ＥＧＴＡ和维拉帕米预处理不能阻断ＰＤ作用，但加入钠通道阻断剂河豚毒素（１μｍｏｌ·Ｌ－１）则可完全阻断ＰＤ的去极化作用。结论ＰＤ对细胞内钙、ｐＨ有双向调节作用，正常情况下ＰＤ增加细胞内游离钙及升高ｐＨ以提高血管张力，休克时ＰＤ降低细胞内钙浓度及降低细胞内ｐＨ以降低血管张力，使血管扩张。此外ＰＤ还可能通过促进细胞外钠离子?
Objective To investigate the mechanism of polydatin (PD) in improving microcirculation in shock animals. Methods The femoral artery was exsanguinated to replicate the shock model. The mesenteric arterioles were digested with pronase E to separate single vascular smooth muscle cells (VSMC). The cells were then labeled with different fluorescent dyes and the intracellular calcium was measured on a laser confocal microscope ([Ca2+ i) Changes in pH and membrane potential. Results PD (04mmol·L-1) decreased the concentration of [Ca2+]i in VSMCs of shock rats significantly within 10 minutes to 784%±56% before dosing, and the pH decreased to 728%. ±82%; while in the normal control group, the [Ca2+]i of VSMC increased by 175%±63% and the pH increased by 34%±101%. When pretreated with calcium channel blocker verapamil (50 μmol·L-1) for 10 min before PD, the [Ca2+]i and pH of the animals were significantly decreased regardless of shock. In addition, PD caused a negative value of VSMC membrane potential in normal and shock rats, and a depolarization reaction appeared. Pretreatment with EGTA and verapamil failed to block PD, but the addition of the sodium channel blocker tetrodotoxin (1 μmol·L-1) completely blocked the depolarization of PD. Conclusion PD has two-way adjustment effect on intracellular calcium and pH. In normal condition, PD increases intracellular free calcium and increases pH to increase vascular tone. In shock, PD decreases intracellular calcium concentration and decreases intracellular pH to reduce vascular tension. Blood vessels dilate. In addition, PD may also promote extracellular sodium ions.