Investigation Of Mechanism Of Rat' Myocardial Damage With Epirenamine During Cardiopulmonary Resuscitation

Objective: After cardiopulmonary resuscitation, cardiac insufficiency is important reason that death rate of patient is high at acute stage. To investigate epirenamine's myocardial damage condition before ROSC'rat, during CPR. To investigate relationehip and possible mechanism between myocardial damage andβ1-AR. Methods: Fifty SD male were randomly divided into groups 4: blank group (A, n=10); resuscitation control group (B, n=10); standard-dose epinephrine group (C, n=15); high-dose epinephrine group (D, n=15) .To apply rat CPR'model, to anesthetize experimental rat, incision of trachea and to put arterial and venous cannual. except blank group, the rest group will occlude trachea cannula at end expiration, to result rat's cardiac arrest. After 5 min of rat's cardiac arrest, trachea cannula would be unclamped to connect breathing machine and assist respiration, meanwhile we would carry out closed cardiac massage and inject epinephrine through caudal vein. Groups C and D will stop CPR and observe for 15 second to remain heart's sample after appearing independent cardiac rhythm. Pulse wave arterial blood pressure (MAP)≥60mmhg, group B don't inject epinephrine and directly remain heart's sample after 30 secend of closed cardiac massage. This sample would be detected for vigor of ATPase, SOD and concentration of MDA, cAMP, then to take statistical analysis. Heart's sample would be observed ultramicrostructure of cardic muscle cell through electron microscope. Results: Concetration of cardiac muscle'MDA in groups A?B is lower than groups C, D (P<0.01). Concetration of cardiac muscle'MDA in group C is lower than groups D (P<0.05).Vigors of cardiac muscle'ATPase, SOD in groups A, B is higher than groups C, D (P<0.01), and group C is higher than group D (P<0.01). There was no significant difference in cardiac muscle'cAMP concentration between group C and group D (P>0.05). Transmission electron microscopy showed the myocardial cell damage performance in rats after CPR. Nuclear deformation, marginated chromatin, the nuclear membrane rupture, pyknosis, mitochondrial swelling, ridge fracture or even disappear.There was significant difference between group C and group D in observing ultramicrostructure of cardiac muscle cell. Conclusion: During CPR, high-dose epinep- hrine has increased myocardial damage before ROSC compare with standard-dose epinephrine, but high-dose epinephrine has increased myocardial damage which might be not effect ofβ1-AR'increased excitability.