CARDIAC MYOCYTE FUNCTIONAL AND BIOCHEMICAL-CHANGES AFTER HYPOTHERMIC PRESERVATION IN-VITRO - PROTECTIVE EFFECTS OF STORAGE SOLUTIONS

In this study, we evaluated cardiac myocyte viability and function und er hypothermic conditions with four types of storage solutions. saline solution, Euro-Collins solution, University of Wisconsin solution, an d MCDB 107 medium. Cardiac myocytes were isolated from neonatal rat ve ntricles by collagenase dispersion and cultured for 4 days with MCDB 1 07 medium. A total of 12.5 x 10(5) myocytes per culture dish was used and the myocytes were incubated at 4 degrees C for 6, 12, 18, and 24 h ours in the various storage solutions, After each incubation time, cre atine kinase and lactate dehydrogenase were measured in the storage so lutions. The myocytes were then incubated for 24 hours at 37 degrees C to evaluate the recovery of the myocyte beating rate. In the MCDB 107 group (n = 7), the recovery ratio of myocyte beating rate was complet e by 12 hours, then decreased to 44.8% of control (beating rate before hypothermic incubation) at 24 hours, The saline, Euro-Collins, and Un iversity of Wisconsin groups (n = 7 each) had significantly lower reco very ratios than the MCDB 107 group (at 12 hours: 61.0%, 32.2%, and 48 .9%; at 18 hours: 0.0%, 5.5%, and 15.1% of control, respectively). Rel ease of creatine kinase and lactate dehydrogenase in the MCDB 107 grou p gradually increased and at 24 hours was 143.2 mIU/flask and 486.2 mI U/flask, respectively. However, the saline and University of Wisconsin groups had significantly increased creatine kinase and lactate dehydr ogenase values at 24 hours (creatine kinase: 334.6 and 319.6 mIU/flask ; lactate dehydrogenase: 821.6 and 654.4 mIU/ flask, respectively). Th e Euro-Collins group showed the greatest increase in both markers (cre atine kinase: 1587.5, lactate dehydrogenase: 2106.9 mIU/flask). In sum mary, saline and University of Wisconsin solutions showed a beneficial effect on recovery of myocyte viability at 12 hours compared with Eur o-Collins solution, however MCDB 107 medium had the best overall prote ctive effect on cultured myocytes. Accordingly, alternate hypothermic storage solutions, such as cell-culture medium, may have protective ch aracteristics that are suitable for cardiac preservation.