Protective effects of hypovolemic hypotension preconditioning on cardiopulmonary function after myocardium ischemia/reperfusion injury.
OBJECTIVE
To identify the protective effects of hypovolemic hypotension preconditioning on cardiopulmonary function after myocardial ischemia/reperfusion injury and to explore the possible mechanism.


METHODS
Twenty-four male white rabbits were randomly assigned to two groups. In the control group, ischemia/reperfusion animals(Group I/R, n=10) were subjected to thirty-minute occlusion of left anterior descending coronary artery and two-hour reperfusion. Animals in hypovolemic hypotension preconditioning group (Group HHP, n=14) experienced brief systemic ischemia preconditioning through blood withdrawal to lower blood pressure to 40%-50% of the baseline before myocardial ischemia/reperfusion. Hemodynamic parameters were recorded. Blood sample was taken to measure superoxide dismutase (SOD), malondialdehyde (MDA) and nitrogen monoxide (NO) changes with blood gas analysis. Myocardium specimens were sampled to examine apoptosis-related gene interleukin-1 beta converting enzyme (ICE) mRNA.


RESULTS
Cardiac mechanical function and lung gas exchange remained stable in Group HHP with a significant increase in NO level; while in Group I/R without preconditioning, cardiopulmonary dysfunction was present after 2 h reperfusion associated with a significant reduction in NO formation and an increase in MDA (P<0.001). There was negative expression of ICE mRNA in the two groups.


CONCLUSIONS
Hypovolemic hypotension preconditioning significantly improves cardiopulmonary function and increases NO formation and the protective benefit associated with hypovolemic hypotension preconditioning of the heart may be regulated through NO mediated mechanism.
Chen
Xue-Jun
XJ
Department of Anesthesiology, Renmin Hospital, Wuhan University, Wuhan 430060, China. xue0308@mail.tom.com.cn
Wang
Xin
X
Xia
Zhong-Yuan
ZY
Luo
Tao
T
Tu
Zhong-Fan
ZF
D000818:Animals; D001794:Blood Pressure; D001810:Blood Volume; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology* / Q000517:prevention & control; D009569:Nitric Oxide / Q000097:blood; D011817:Rabbits; D013482:Superoxide Dismutase / Q000097:blood
D009569:Nitric Oxide; D008315:Malondialdehyde; D013482:Superoxide Dismutase