侧流暗场成像技术观察内毒素休克兔小肠绒毛与舌下微循环改变

目的:利用侧流暗场(sidestream dark-field,SDF)成像技术观察比较内毒素休克兔经液体复苏至同一目标血压水平下小肠绒毛微循环及舌下微循环变化的异同。方法:新西兰大白兔60只,随机分为绒毛组及舌下组,每组30只。2组均行体外回肠造口术,用细菌脂多糖注射建立内毒素休克模型。建模成功后用乳酸林格氏液以复苏剂量30 mL·kg~(-1)·h~(-1)进行液体复苏使平均动脉压(MAP)达到80 mmHg为目标血压。若经单纯液体复苏,血压仍不能达标者,则予以去甲肾上腺素0.5~1μg·kg~(-1)·min~(-1)维持至目标血压。通过SDF成像技术持续观察2组动物休克前后以及液体复苏后的小肠绒毛及舌下微循环灌注指标:绒毛血管数量(vessels per villus,VV)、微血管血流指数(microvascular flow index,MFI)、灌注绒毛比例(proportion of perfused villi,PPVi)、绒毛边界量化评分、绒毛血管评分、总的血管密度(total vessel density,TVD)、灌注血管密度(perfused vessel density,PVD)、灌注血管比例(proportion of perfused vessels,PPVe)等的变化并比较两者灌注特点的异同。结果:休克后,小肠绒毛MFI、PPVi以及舌下微循环MFI、PPVe、TVD、PVD较休克前均显著下降(P0.01),其中小肠绒毛微循环MFI显著低于舌下微循环(P0.01);经液体复苏至MAP达到目标血压后,小肠绒毛MFI、PPVi以及舌下微循环MFI、PPVe、TVD、PVD较休克后均有明显上升(P0.05),但复苏后的小肠绒毛微循环MFI仍明显低于舌下微循环(P0.01)。结论:内毒素休克兔小肠绒毛与舌下微循环灌注变化有差异,休克后小肠绒毛微循环灌注下降程度较舌下微循环更显著,而液体复苏后小肠绒毛微循环灌注恢复程度亦低于舌下微循环。

Changes of small intestine villus and sublingual microcirculation in rabbits during endotoxic shock observed by sidestream dark-field imaging

AIM: To investigate the changes of small intestine villus and sublingual microcirculation perfusion in the rabbits during endotoxic shock by sidestream dark-field imaging (SDF) after resuscitation to a mean arterial pressure (MAP) level.METHODS: New Zealand white rabbits (n=60) were randomly divided into 2 groups (group of villus and group of sublingua). The fistula operation of ileum was performed. Lipopolysaccharide was injected to establish endotoxic shock model, and fluid resuscitation (lactated Ringer's solution, 30 mL·kg^-1·h^-1) was given to maitain the MAP of the animals to 80 mmHg. Continuous norepinephrine was intravenously injected at 0.5~1 μg·kg^-1·min^-1 only if fluid therapy did not maintain the MAP level. The changes of microcirculatory perfusion indexes in small intestine villus and sublingual tissues such as vessels per villus (VV), microvascular flow index (MFI), proportion of perfused villi (PPVi), villus border score, villus vessel score, total vessel density (TVD), perfused vessel density (PVD) and proportion of perfused vessels (PPVe) were continuously observed and recorded by SDF before shock, during shock and after fluid resuscitation. RESULTS: MFI and PPVi in small intestine villus, and MFI, PPVe, TVD and PVD in sublingual tissues were significantly decreased after shock(P<0.01). Compared with MFI in sublingual microcirculation, MFI in villus was significantly decreased (P<0.01). MFI and PPVi in small intestine villus, and MFI, PPVe, TVD and PVD in sublingual tissues were improved after recovered to the target MAP by fluid resuscitation (P<0.05). However, MFI in small intestine villus was significantly lower than that in sublingual tissues after fluid resuscitation (P<0.01).CONCLUSION: The difference between small intestine villus and sublingual microcirculation perfusion during endotoxic shock is observed. The descent degree of microcirculation perfusion in small intestine villus is larger than that in sublingual tissues after shock, and the recovery degree of small intestine villus microcirculation is lower than that of sublingual microcirculation afer fluid resuscitation.