[Effects of oxygenation and/or SOD on addition to St. Thomas' Hospital cardioplegic solution]

The effects of oxygenation (95% O2 + 5% CO2) and/or SOD (400 mg/l) on addition to St. Thomas' Hospital cardioplegic solution were examined by hemodynamic, cytochemical and biophysical assessments in the isolated working rat heart subjected to hypothermic ischemic arrest (22 degrees C in temperature, 180 min in ischemic time) with multidose cardioplegic infusion. According to the feature of used cardioplegic solution, thirty-two rats were divided into four groups (8 animals per group): That is, Group I; O2 (+) SOD (+), Group II; O2 (-) SOD (+), Group III; O2 (+) SOD (-), Group IV (control); O2 (-), SOD (-). Aortic flow (AF) recovery, expressed as a percent of pre-arrest AF, was 76.7 +/- 11.7% in Group I, 66.9 +/- 7.1% in Group II, 73.9 +/- 11.6% in Group III and 57.7 +/- 12.9% in Group IV (mean +/- SD). Differences in recovery between Group I vs III and Group III vs IV approached statistically significance (respectively, p < 0.01, p < 0.05). The birefringence ratio (ATP value/air value) of the biopsy specimen was 2.49 +/- 0.53 in Group I, 1.96 +/- 0.44 in Group II, 2.04 +/- 0.29 in Group III and 1.65 +/- 0.39 in Group IV (mean +/- SD). Difference between Group I and Group IV indicated statistically significance (p < 0.05). The birefringence ratio (X) had good correlation with the AF recovery ratio (Y): Y = 29.7 + 19.1X (R = 0.74). No statistical difference was seen from cytochemical assessment (myosin ATPase stain) in four groups.(ABSTRACT TRUNCATED AT 250 WORDS)