[Studies on the behavior of lipid peroxide in reperfusion induced arrhythmia]

Lipid peroxidation of the cell membrane is one of the most important factors of reperfusion induced arrhythmia (RIA). To determine the role of lipid peroxidation in RIA, lipid peroxide (LPO) and superoxide dismutase (Total, Mn-SOD) were examined in this experiment. Thirty-four male Donryu strain rats (250-350 g body weight) were studied. After left thoracotomy and 5-minute ligature of LAD coronary artery, reperfusion was done under artificial ventilation with room air. The electrocardiogram (ECG) was recorded via standard limb leads. Twenty-four rats were divided into 5 groups and the heart tissue and blood samples were collected 1. preligature 2. after 1-minute ligature 3. after 4-minute ligature 4. 1-minute after declamping and 5. 10-minute after declamping. To examine the correlation between LPO and duration of RIA, samples from another 10 rats were collected as soon as RIA disappeared. LPO, SOD, CPK, and MDH (malate dehydrogenase) were measured in all samples. The total SOD level in heart tissue decreased after reperfusion (p less than 0.05). The heart tissue LPO (t-LPO) decreased after ligature (p less than 0.05), but each value in 2. to 5. was lower than 1., and no increase was found after reperfusion. A negative correlation of R = 0.87 (p less than 0.01) was found between t-LPO and RIA duration, but a positive correlation of R = 0.79 (p less than 0.01) was found between t-LPO and CPK. Moreover, the LPO level was lower in the RIA occurrence group than in the non-occurrence group (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)