Cardioprotection Afforded by St Thomas Solution Is Enhanced by Emulsified Isoflurane in an Isolated Heart Ischemia Reperfusion Injury Model in Rats

ObjectiveThe purpose of this study was to investigate whether adding emulsified isoflurane to St Thomas cardioplegia solution could enhance the cardiac protection after cardioplegic arrest in rats.DesignA randomized, blind study.SettingA university laboratory.ParticipantsThirty male Sprague-Dawley rats.InterventionsThirty isolated heart preparations were randomly divided into 3 groups (n = 10/group) according to the different cardioplegia solutions being given: St Thomas solution mixed with emulsified isoflurane (containing 2.8% of isoflurane, group EI), St Thomas solution mixed with emulsified Intralipid (Huarui Pharmacy, Wuxi, Jiangsu, China) (group EL), and St Thomas solution alone (group St). In the 35-minute normothermic ischemia period, infusion of cardioplegia solution was repeated every 15 minutes. After the 35-minute ischemia period, the heart was perfused with Krebs-Henseleit buffer for another 2 hours.Measurements and Main ResultsThe functional parameters of the heart were monitored throughout the experiments. The coronary effluent was collected for measuring the activity of CK-MB 30 minutes after reperfusion, and the infarct size was assessed at the end of reperfusion. The infarct size in group EI (24% ± 4%) was reduced when compared with that in group EL (31% ± 8%, p < 0.05) and group St (43% ± 9%, p < 0.001). The CK-MB activity in group EI was decreased significantly when compared with that in group EL and group St (p < 0.05). The functional recovery in group EI also was improved. Compared with standard St Thomas solution alone, adding 30% Intralipid alone also significantly reduced the infarct size and the CK-MB leakage and improved the recovery of the mechanical function.ConclusionsSt Thomas cardioplegia solution supplemented with emulsified isoflurane enhanced its cardioprotection in an isolated heart ischemia reperfusion injury model in rats.