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目的探讨改良极化液对体外循环(ECC)小型猪心脏功能保护作用研究。方法小型猪12头随机分为两组,组1为对照(CON)组,麻醉后经外周静脉输入乳酸林格氏液20 ml/h;组2为极化液(GIK)组,与CON组在同一时间以同样速度输注GIK。全麻诱导插管后,建立ECC,过程为转机、阻闭、开放各30 min后停止ECC。检测麻醉诱导后至开放升主动脉120 min期间的血糖(BG)、乳酸(Lac)、平均动脉压(MAP)、左心室舒张末压(LVEDP)和左心室收缩峰压(LVPSP),并计算左心室发展压(LVDP)变化,同期对心肌组织行电镜检测及Western blotting分析。结果 ECC后两组BG水平显著上升,在开放升主动脉120 min时达峰值,胰岛素水平也显著升高,但两组间无显著性差异(P>0.05);两组Lac水平在ECC后有所上升,在开放升主动脉后上升更为显著,GIK组显著低于CON组,在ECC 5 min、开放升主动脉60 min及120 min有显著性差异(P<0.05);所有实验猪在ECC后MAP及心室压力出现显著变化,表现为除LVEDP外的所有压力值均有不同程度下降,而LV-EDP显著升高,GIK组LVPSP、LVDP在开放升主动脉80 min后显著高于CON组(P<0.05);GIK组MAP在开放升主动脉20min后即表现为高于CON组(P<0.05);而GIK组的LVEDP在开放升主动脉后一直低于CON组(P<0.05)。电镜结果显示:ECC后CON组心肌线粒体明显肿胀,而GIK组线粒体改变远较CON组为轻,Western blotting检测结果提示GIK组蛋白激酶B(Akt)磷酸化程度显著高于CON组,而6-磷酸果糖氨基转位酶(GAFT)又显著低于CON组。结论 ECC下心脏手术可导致不同程度心肌损伤,进而引起应激性高血糖、乳酸增高、心肌收缩功能降低,而GIK对ECC后心肌细胞有明显保护作用,其机制与GIK有效激活Akt通道,降低己糖胺活性有关。
Objective To investigate the protective effect of modified polar fluid on heart function of cardiopulmonary bypass (ECC) miniature pigs. Methods 12 mini-pigs were randomly divided into two groups. Group 1 was control group (CON), and lactated Ringer’s solution (20 ml / h) was given via peripheral vein after anesthesia. Group 2 was treated by GIK group, GIK is infused at the same rate at the same time. After induction of general anesthesia intubation, the establishment of ECC, the process for the transfer, blocking, open the stop after 30min ECC. The blood glucose (BG), lactic acid (Lac), mean arterial pressure (MAP), left ventricular end-diastolic pressure (LVEDP) and left ventricular systolic pressure (LVPSP) during the 120 min after induction of anesthesia were measured. Left ventricular development pressure (LVDP) changes, the same period on myocardial tissue underwent electron microscopy and Western blotting analysis. Results After BG, the levels of BG increased significantly in the two groups, reaching the peak at 120 min after opening ascending aorta, and the insulin level also increased significantly, but there was no significant difference between the two groups (P> 0.05) (P <0.05). There was a significant difference (P <0.05) between 5 min after ECC and 60 min after opening of the ascending aorta in all rats After ECC, there was a significant change in MAP and ventricular pressure, showing that all the pressure values except LVEDP decreased to some extent and LV-EDP increased significantly. LVPSP and LVDP in GIK group were significantly higher than CON (P <0.05). The MAP of GIK group was significantly higher than that of CON group (P <0.05) after 20 minutes of ascending aorta opening, while the LVEDP of GIK group was lower than that of CON group after open ascending aorta ). Electron microscopy showed that myocardial mitochondria were significantly swollen in CON group after ECC and mitochondrial changes in GIK group were much lighter than those in CON group. Western blotting indicated that phosphorylation of Akt in GIK group was significantly higher than that in CON group, while 6- The phosphofructose aminotransferase (GAFT) was significantly lower than the CON group. Conclusions Cardiac surgery under ECC can lead to different degree of myocardial injury, which leads to stress hyperglycemia, increase of lactate and decrease of myocardial contractile function. However, GIK can obviously protect cardiomyocytes after ECC, and its mechanism and GIK activate Akt channel and decrease Hexosamine activity.