trilinolein and Myocardial-Infarction

Trilinolein is a triacylglycerol purified from a commonly used traditional Chinese medicine Panax notoginseng. Trilinolein has been reported to provide a number of beneficial effects including reducing thrombogenicity and arrhythmias and increasing erythrocyte deformability. Additionally, trilinolein has been reported to be an antioxidant, which can counteract free radical damage associated with atherogenesis, and myocardial damage seen with ischaemia and reperfusion. These pharmacologic effects may explain the perceived benefits derived from treating circulatory disorders with the herb over the centuries.

Topics: Animals; Anti-Arrhythmia Agents; Antioxidants; Cardiotonic Agents; Humans; Myocardial Infarction; Panax; Plants, Medicinal; Platelet Aggregation; Triglycerides

In a previous study we demonstrated that trilinolein, a natural plant triacylglycerol, is a novel myocardial protective agent in vivo. The mechanism probably involves an antioxidant effect. This work investigated the mechanism of myocardial protection of trilinolein to determine if inhibition of calcium influx and alteration of activity of superoxide dismutase are involved. In isolated cardiomyocytes, pretreatment with trilinolein at a low concentration of 10(-9) M effectively reduced 45Ca2+ influx stimulated by hypoxia/normoxia by 34%. In isolated perfused rat heart subjected to 60 min global hypoxemia without reperfusion, pretreatment with 10(-7) M trilinolein for 15 min reduced infarct size by 37%. Assay of superoxide dismutase-mRNA by Northern blot analysis in in vivo rat heart subjected to 30 min ischaemia and 10 min reperfusion showed pretreatment with 10(-7) M trilinolein had a synergistic action with antioxidant systems preventing the rise in superoxide dismutase-mRNA. These results reconfirm the myocardial protection of trilinolein and suggest it may be related to antioxidant activity and inhibition of 45Ca2+ influx.

Topics: Animals; Blotting, Northern; Calcium; Calcium Radioisotopes; Cardiomyopathies; Male; Myocardial Infarction; Myocardial Ischemia; Myocardium; Oxygen; Plants, Medicinal; Rats; Rats, Sprague-Dawley; RNA, Messenger; Superoxide Dismutase; Triglycerides

Trilinolein, a triacylglycerol with linoleic acid as the only fatty acid residue in all esterified positions of glycerol, was previously found to improve erythrocyte deformability in vitro. In this study, the in vivo antiarrhythmic and anti-ischemic effects of trilinolein in coronary ligated rats were investigated. Male Sprague-Dawley rats were anaesthetized with urethane. Trilinolein, at dosages ranging from 10(-11) to 10(-7) g/kg, was administered intravenously 15 min before ligation of coronary artery. Also, the effect of trilinolein on arrhythmia was studied by ligating the coronary artery for 30 min, then reperfusing myocardium for 10 min. During the 30-min ischemia, trilinolein reduced not only the number of ectopic beats but also the incidence rate and duration of ventricular tachycardia. At 10(-7) g/kg, trilinolein completely suppressed all ventricular arrhythmias. Ventricular arrhythmias during 10 min reperfusion were also reduced by trilinolein at similar dosages. Furthermore, the effect of trilinolein on infarct size was evaluated by occluding the coronary artery for 4 h before the infarct zone was stained and weighed. In rats subjected to 4 h coronary ligation, pretreatment with 10(-7) g/kg trilinolein at 15 min prior to the coronary ligation significantly reduced infarct size. Trilinolein may protect myocardium against ischemic injury and suppress arrhythmia during ischemia and reperfusion.

Topics: Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Blood Pressure; Coronary Vessels; Electrocardiography; Heart Rate; Male; Myocardial Infarction; Myocardial Reperfusion; Rats; Rats, Sprague-Dawley; Triglycerides