Objective: To explore the effects and mechanisms of Dendrobium nobile Lindl. alkaloids (DNLA) on myocardial lipid metabolism during ischemia-reperfusion in dogs undergoing cardiopulmonary bypass (CPB). Methods: Twenty-four healthy hybrid dogs, half male and half female, were randomly divided into sham group, model group, solvent control group and treatment group (DNLA, 6 mg/kg) (n=6), all of which were established with CPB. Except for the sham group, the aorta of the other groups was occluded for 60 min and then reopened. The uptake rate of free fatty acids, the concentration of long-chain acyl coenzyme A (LCACoA), mRNA and protein expression of fatty acid translocase enzyme/CD36 (FAT/CD36) in myocardial tissue and the cardiac function indexes were measured at 4 time points: before cardiopulmonary bypass (T1), 15 min (T2), 60 min (T3), and 90 min (T4) after reperfusion in each group. Results: Before CPB, there were no statistically significant differences in the uptake rate of free fatty acids, the concentration of LCACoA and mRNA expression of FAT/CD36 in myocardial tissue in each group (P>0.05). After the opening of the aorta, the above indexes in model group [(35.8±4.7)%, (8.55±1.51) nmol/g, 3.23±0.68] and treatment group [(27.4±2.7)%, (6.10±1.38) nmol/g, 2.20±0.56] were higher than those in sham group [(19.6±3.9)%, (4.16±0.81)nmol/g, 1.19±0.52], which were the highest at T2, and then gradually decreased (all P<0.05). Compared with the model group, the increase of above indicators in the treatment group was significantly lower at T2 (all P<0.05). Before CPB, there was no statistically significant differences in cardiac function indexes [left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP) and±dp/dtmax] among the groups (P>0.05). After the aorta was opened, the above indexes in model group [(76.5±9.1) mmHg, (31.1±2.9) mmHg, (1.2±0.4) mmHg/ms, (-0.9±0.1) mmHg/ms] and treatment group [(92.9±8.7) mmHg, (25.3±3.6) mmHg, (1.8±0.4) mmHg/ms, (-1.3±0.1) mmHg/ms] were lower than those in sham group [(165.5±12.9) mmHg, (6.5±0.5) mmHg, (3.3±0.6) mmHg/ms, (-2.9±0.3) mmHg/ms] (all P<0.05), but the impairment degree of cardiac function indicators in treatment group was significantly lower than that those in model group (all P<0.05). Conclusion: During CPB in dogs, DNLA can inhibit the abnormal expression of FAT/CD36, decrease the uptake of free fatty acids, and reduce the abnormal accumulation of LCACoA in myocardium,thereby alleviating the myocardial injury after ischemia-reperfusion.
目的： 探讨金钗石斛总生物碱对犬体外循环（CPB）过程中缺血再灌注心肌脂代谢的影响及其可能机制。 方法： 健康成年中华田园犬24只，雌雄各半，体重（11.2±1.5）kg，随机分为假手术组、模型组、溶剂对照组、治疗组（金钗石斛总生物碱，剂量为6 mg/kg）4个组（每组6只），均建立体外循环，除假手术组外其余各组均阻断主动脉60 min后再开放。各组于体外循环转流前（T1）和开放主动脉再灌注15 min（T2）、60 min（T3）、90 min（T4）4个时间点检测心肌对血浆游离脂肪酸的摄取率、心肌组织中长链脂肪酰辅酶A（LCACoA）浓度，分析心脏功能及测定心肌组织内脂肪酸转位酶（FAT/CD36）mRNA和蛋白的表达。 结果： 各组犬心肌对血浆游离脂肪酸的摄取率、心肌组织中LCACoA浓度及FAT/CD36 mRNA的表达在流转前差异均无统计学意义（均P>0.05），主动脉开放后（T2）以上指标模型组[分别为（35.8±4.7）%、（8.55±1.51）nmol/g、3.23±0.68]和治疗组[分别为（27.4±2.7）%、（6.10±1.38）nmol/g、2.20±0.56]均高于假手术组[分别为（19.6±3.9）%、（4.16±0.81）nmol/g、1.19±0.52]（均P<0.05），在T2时间点最高，后逐渐下降；同模型组相比，以上指标治疗组的升高幅度偏低（均P<0.05）。各组心脏功能指标：左室收缩压（LVSP）、左室舒张末压（LVEDP）、左室内压最大上升/下降速率（±dp/dtmax）流转前差异均无统计学意义（均P>0.05），主动脉开放后（T2），以上心脏功能指标模型组[分别为（76.5±9.1）mmHg、（31.1±2.9）mmHg、（1.2±0.4）mmHg/ms、（-0.9±0.1）mmHg/ms]与治疗组[分别为（92.9±8.7）mmHg、（25.3±3.6）mmHg、（1.8±0.4）mmHg/ms、（-1.3±0.1）mmHg/ms]均低于假手术组[分别为（165.5±12.9）mmHg、（6.5±0.5）mmHg、（3.3±0.6）mmHg/ms、（-2.9±0.3）mmHg/ms]（均P<0.05），但治疗组的心脏功能指标受损程度低于模型组（均P<0.05）。 结论： 金钗石斛总生物碱在犬体外循环过程中，可通过抑制FAT/CD36在心肌组织中的表达异常，降低心肌对游离脂肪酸的摄取，减少LCACoA在心肌组织内异常蓄积，达到减轻缺血再灌注后心肌损伤的作用。.
Keywords: Cardiopulmonary bypass; Dendrobium nobile Lindl. alkaloids; Long chain acyl coenzyme A; Myocardial reperfusion injury.