谷氨酰胺预处理对体外循环下心脏瓣膜置换术患者心肌的保护作用

Protection Effect of Glutamine Pretreatment on the Cardiomyocytes of Patients Undergoing Cardiac Valve Replacement in Cardiopulmonary Bypass

目的研究谷氨酰胺预处理对体外循环下心脏瓣膜置换术患者心肌的保护作用。方法将60例择期在体外循环下行二尖瓣和/或主动脉瓣置换术患者随机分为谷氨酰胺预处理组(n=30)和对照组(n=30),谷氨酰胺预处理组患者在手术前4天开始经外周静脉给予谷氨酰胺0.5g/kg,每天一次,手术当天在麻醉诱导后切皮前经中心静脉给予相同剂量的谷氨酰胺,总计5次;对照组仅给予等量的生理盐水。两组麻醉方法及用药相同。分别于麻醉后切皮前(T1)、开放主动脉后60min(T2)、6h(T3)、12h(T4)、24h(T5)分别抽取桡动脉血10mL测定心肌肌钙蛋白I。并于开放主动脉后30min取右心耳心肌组织约1～2g,做病理切片检查。记录各个时点患者的血压以及患者停转流后多巴胺及硝普钠的用量。结果光镜下,对照组心肌间隙及血管周围有大量白细胞浸润,而谷氨酰胺预处理组则明显少于对照组;两组心肌肌钙蛋白I从T2时点开始显著增加(P<0.05),T4时点达到峰值,以后逐渐下降,且谷氨酰胺预处理组自T2时点开始较对照组显著降低(P<0.05);两组在硝普钠用量差别不大的情况下,谷氨酰胺预处理组多巴胺的用量显著低于对照组。结论谷氨酰胺预处理对体外循环下心脏瓣膜置换术患者心肌具有保护作用。

Aim To investigate the the protection effect of glutamine pretreatment on the cardiomyocyte of the patients undergoing cardiac valve replacement in cardiopulmonary bypass.Methods Sixty patients undergoing cardiac valve replacement under CPB were randomly divided into two groups：control group （n=30） and glutamine pretreatment group （n=30）.The patients in glutamine pretreatment group had intravenous injection by drip with glutamine 0.5 g/kg through the peripheral vein,four days before operation,once a day.After endotracheal intubation,the same volume glutamine was injected through the centre vein at the operation day.Only the same volume of sodium chloride was injected in control group.The same anesthetic drug and plan were given in both groups.To examine serum cardiac troponin I （cTnI）,the arterial blood samples were drawn at the following time point：after endotracheal intubation （T1）,60 min （T2）,6 h （T3）,12 h （T4） and 24 h （T5） after aortic de-clamped.The right atrial tissue samples 1～2 g were taken for microscopic examination 30 min after aortic de-clamped.The amount of dopamine,sodium nitroprusside were used and the rate of spontaneous heart resuscitation in both groups were recorded.Results By light microscopy,histochemical staining showed that there were a great number of leucocyte infiltration in cardiac muscle and capillary vessel of the patients in control group,and the degree of leucocyte infiltration decreased in glutamine pretreatment group.The concentration of serum cTnI in both groups was increased significantly from T2 to T5 （P〈0.05）,and it reached to maximum at T4,but the value of the concentration of plasma cTnI at all time points was lower in glutamine pretreatment group except T1 than that in control group （P〈0.05）.Less dopamine was used in glutamine pretreatment group （P〈0.05）,while sodium nitroprusside used did not show significant difference in both groups.Conclusion Glutamine pretreatment has protection effects on the patients undergoing cardiac valve replacement in cardiopulmonary bypass.