Nitric oxide attenuates cardiomyocytic apoptosis via diminished mitochondrial complex I up-regulation from cardiac ischemia-reperfusion injury under cardiopulmonary bypass.
OBJECTIVE
This study tested the hypothesis that cardioplegic solution supplemented with a nitric oxide donor agent attenuates postischemic cardiomyocytic apoptosis by reduction of mitochondrial complex I up-regulation during global cardiac arrest under cardiopulmonary bypass.


METHODS
Twenty-four anesthetized dogs supported by total vented bypass were divided evenly into 4 groups (n = 6) and subjected to 60 minutes of hypothermic ischemia followed by 4 degrees C multidose crystalloid cardioplegic solution infusion. Hearts received either standard crystalloid cardioplegic solution (control), crystalloid cardioplegic solution supplemented with 2 mmol/L L-arginine (L-Arg group), crystalloid cardioplegic solution supplemented with 400 micromol/L N(G)-monomethyl-L-arginine (L-NMMA group), or crystalloid cardioplegic solution supplemented with 100 micromol/L of NO donor compound (3-morpholinosydnonimine; SIN-1 group). After 60 minutes of cardioplegic arrest, the heart was reperfused for a total of 240 minutes after discontinuation of bypass. The occurrence of cardiomyocytic apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling and Western blot analysis of caspase-3.


RESULTS
The occurrence of cardiomyocytic apoptosis was significantly reduced in SIN-1 and L-Arg groups compared with the control group. Mitochondrial complex I mRNA was up-regulated in the control group, and its expression was significantly higher in the L-NMMA group but significantly reduced in the SIN-1 and L-Arg groups. Western blot analysis of Bcl-2 and cytochrome c, an index of mitochondrial damage in postischemic myocardium, revealed a similar pattern.


CONCLUSIONS
Nitric oxide-supplemented crystalloid cardioplegic solution diminished postischemic cardiomyocytic apoptosis after global cardiac arrest under cardiopulmonary bypass, possibly via prevention of mitochondrial complex I up-regulation.
Division of Thoracic and Cardiovascular Surgery, Chang Gung Memorial Hospital, 5 Fu-Hsing Street, Kweishan, Taoyuan, Taiwan 333. yehcc1@cgmh.org.tw
Chi-Hsiao
CH
Yeh
Yu-Min
YM
Lin
Yi-Cheng
YC
Wu
Yao-Chang
YC
Wang
Pyng Jing
PJ
Lin
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D004285:Dogs; D042967:Electron Transport Complex I / Q000187:drug effects / Q000502:physiology*; D008981:Molsidomine / Q000031:analogs & derivatives / Q000627:therapeutic use*; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000209:etiology / Q000517:prevention & control*; D032383:Myocytes, Cardiac; D009569:Nitric Oxide / Q000627:therapeutic use*; D020030:Nitric Oxide Donors / Q000627:therapeutic use*; D015854:Up-Regulation
D020030:Nitric Oxide Donors; D009569:Nitric Oxide; C002385:linsidomine; D008981:Molsidomine; D042967:Electron Transport Complex I