Objective: The 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.
Design: A randomized, blind study.
Setting: A university laboratory.
Participants: Thirty male Sprague-Dawley rats.
Interventions: Thirty 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 results: The 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.
Conclusions: St Thomas cardioplegia solution supplemented with emulsified isoflurane enhanced its cardioprotection in an isolated heart ischemia reperfusion injury model in rats.
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