聚氧化乙烯对大鼠腹主动脉血流量及下肢循环阻力的影响

Effects of polyethylene oxide at different concentrations on abdominal aortic blood flow and vascular resistance in rats

目的观察应用聚氧化乙烯(PEO)后大鼠腹主动脉血流量及下肢循环阻力的变化,评价不同剂量PEO的减阻效果差异及其安全性,为进一步开展减阻剂相关研究奠定基础。方法Wistar大鼠32只随机分为4组。经腹腔麻醉后,腹主动脉安置多普勒血流探头监测血流量。分别经尾静脉泵入生理盐水(对照组)、1×10-6g/ml(低剂量组)、1×10-5g/ml(中剂量组)和5×10-5g/ml(高剂量组)。泵入速度均为5g/ml,持续20min。自给药开始至停药后20min内,连续监测腹主动脉血流量、心电图、颈动脉压、中心静脉压、髂动脉压和髂静脉压。根据流量及压力差推算下肢循环阻力。结果除高剂量PEO治疗组在给药过程中,大鼠血压下降(P=0.014)外,其余各组大鼠给药前后血压均无明显变化。全部大鼠在实验过程中心率、中心静脉压均无明显变化。泵入盐水对腹主动脉血流量及下肢循环阻力无影响(P>0.05)。低剂量PEO轻度增加腹主动脉血流量(P=0.026),但未能明显降低下肢循环阻力(P=0.052);中剂量PEO不仅显著增加腹主动脉血流量(P<0.001),同时显著减低下肢循环阻力(P<0.001);高剂量PEO在给药4min后腹主动脉血流量达峰值,且伴随下肢循环阻力的降低(P<0.005),但不能持久,很快回落至基线水平。结论PEO作为减阻剂,其减阻效应与给药浓度密切相关。与低剂量组相比,中剂量组的PEO溶液可以平稳、安全地增加腹主动脉血流量,同时降低下肢循环阻力。剂量过高其减阻效能将受到一定的影响。

Objectives To observe the effect of polyethylene oxide （PEO） solution at different concentrations on abdominal aortic blood flow and vascular resistance in rats and evaluate the safety and drag-reducing effect of PEO solution.Methods Thirty-two rats were anesthetized and randomly divided into 4 groups.An ultrasonic flow probe was deployed on the abdominal aorta （5 mm above the common iliac artery） to measure the blood flow.The carotid artery pressure,iliac artery pressure,iliac vein pressure,central venous pressure （CVP） and ECG were also monitored.Saline or different concentrations of PEO [（1×10-6（low）,1×10-5（middle） and 5×10-5（high） g/ml）] were injected in the 4 groups of rats through the caudal vein at a constant rate of 5 ml/h for 20 min,and the changes of the vascular resistance was observed.Results After injections of 1× 10-6 and 1×10-5 g/ml PEO,the abdominal aortic flow increased significantly （P0.05） while the vascular resistance was reduced （Plow=0.052,Pmiddle0.001） as compared to those in the saline control group.Following the injection with 5 ×10-5 g/ml PEO,the abdominal aortic flow increased to a threshold in the initial 4 min,after which it rapidly decreased to approach the baseline levels despite continuous infusion.Blood pressure remained stable after the injections except for 5×10-5 g/mlPEO injection,which resulted in a reduction of the blood pressure by about 10 mmHg （P=0.014）.The heart rate and CVP both underwent no significant changes following the injections.Conclusion The drag-reducing effect of PEO is closely related to its concentration,and compared with 1×10-6 g/ml,1×10-5 g/ml PEO more effectively increases the blood flow and decreases the resistance.The effectiveness and safety of EPO are attenuated at a concentration higher than 5×10-5 g/ml.