[Effect of isoflurane delayed preconditioning on myocardial ischemia reperfusion injury in rabbits].
OBJECTIVE
To investigate the protective effect of isoflurane delayed preconditioning on myocardial ischemia reperfusion injury and the potential mechanism in rabbits.


METHODS
Thirty New Zealand male white rabbits were randomly assigned to 3 groups: Control group; I/R group; and 2.0% isoflurane group. Isoflurane group was exposed to 2.0% isoflurane-100% oxygen for 2 hours. Control group and I/R group were exposed to 100% oxygen for 2 hours and served as untreated controls. Twenty-four hours later I/R group and isoflurane group underwent 40 minutes of coronary occlusion followed by 2 hours of reperfusion. Blood samples were taken from the arterial line at 20 minutes before the occlusion(T1), 20 minutes after the occlusion(T2), 40 minutes after the occlusion(T3), 1 hours after the reperfusion(T4), and 2 hours after the reperfusion(T5) to determine the plasma level of TNF-alpha. At the end of the reperfusion, infarct size and area at risk were defined by Evans and TTC staining. The heart was harvested and levels of the p38MAPK activity were determined by Western blot, and ultrastructures were observed under the electron microscope.


RESULTS
The p38MAPK activity of isoflurane group was significantly lower than that of I/R group (P<0.05). Isoflurane significantly (P<0.05) reduced the infarct size(19.7%+/-2.8% in isoflurane group) of the left ventricular area at risk as compared with the controls (37.8%+/-1.7% in I/R group).The injury of I/R group was worse than that of isoflurane group under the light microscope. Isoflurane group had a lower level of TNF-alpha than I/R group.


CONCLUSIONS
Isoflurane can inhibit p38MAPK activity during myocardial ischemia reperfusion and modulate the cytokine expression, which may be one of the molecular mechanisms of isoflurane delayed preconditioning on cardioprotection.
Ran
Ke
K
Department of Anesthesilogy, Second Xiangya Hospital,Central South University,Changsha, China. rankerk@126.com
Duan
Kai-ming
KM
Zou
Ding-quan
DQ
Li
Zhi-jian
ZJ
Jin
Li-yan
LY
Chang
Ye-tian
YT
D000818:Animals; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000473:pathology / Q000517:prevention & control*; D009206:Myocardium / Q000648:ultrastructure*; D011817:Rabbits; D011897:Random Allocation; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D014409:Tumor Necrosis Factor-alpha; D007530:Isoflurane; D048051:p38 Mitogen-Activated Protein Kinases