[Protective effect of intralipid on myocardial ischemia/reperfusion injury in isolated rat heart].
OBJECTIVE
To investigate whether intralipid could protect perfused hearts of rats against ischemia/reperfusion (I/R) injury when it was administered before (preconditioning) or after the adverse ischemic event (postconditioning), in order to ascertain if intralipid would be a novel therapeutic strategy for myocardial I/R injury.


METHODS
Studies were conducted in Langendorff-perfused isolated rat hearts. Twenty-four male Sprague-Dawley (SD) rats were divided into 3 groups randomly. The experimental procedure consisted of balance perfusion for 50 minutes, warm global ischemia (37 centigrade) for 40 minutes and 120 minutes of reperfusion. Preconditioning of hearts in myocardial preconditioning (I-preC group) consisted of 15 minutes of intralipid followed by 15 minutes of wash out before ischemia for 40 minutes and reperfusion for 120 minutes. In myocardial postconditioning (I-postC group) rat hearts were perfused with intralipid for 15 minutes at the onset of reperfusion. Hearts without intralipid treatment served as ischemic control (ISCH) group. Left ventricular mechanical function [heart rate (HR), left ventricular end-diastolic pressure (LVEDP), left ventricular diastolic pressure (LVDP), maximal change rate of intraventricular pressure rise/down (+/-dp/dt max)] were measured during the experiment, cardiac enzyme activity [creatine kinase (CK), lactate dehydrogenase (LDH)] were determined at 20 minutes after balance and 60 minutes after reperfusion.


RESULTS
Comparing with ISCH group, the LVDP and +dp/dt max in the I-postC group were significantly higher and LVDEP, -dp/dt max were lower when compared with ISCH groups during reperfusion (all P<0.05). There were no significant differences in above indexes in I-preC group. As compared with the ISCH group, the content of LDH and CK in I-preC and I-postC were significantly lower at 60 minutes after reperfusion (all P<0.05). However, there were no significant differences between the I-preC and I-postC groups with respect to the levels of LDH and CK. The infarct size (IS) of I-preC and I-postC was markedly smaller than that of the ISCH group at 120 minutes of reperfusion [(21.6+/-1.8)%, (15.9+/-1.3)% vs. (46.5+/-3.9)%, both P<0.05]. The IS did not differ between the I-preC and I-postC groups (P>0.05).


CONCLUSIONS
Intralipid administered before or after ischemia can decrease the level of CK, LDH and IS during reperfusion in isolated rat hearts. Intralipid postconditioning improves mechanical function.
Liu
Shan-ling
SL
Laboratory of Anesthesia and Critical Care Medicine, West China Hospital, Sichuan University, Chendu 610041, Sichuan, China. lslsxmu@sina.com
Wang
Ying
Y
Wang
Ru-rong
RR
Chai
Yun-fei
YF
Wu
Wei
W
Huang
Han
H
Liu
Jin
J
D000818:Animals; D004195:Disease Models, Animal; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage*; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D005217:Fat Emulsions, Intravenous