Lactate dehydrogenase activity in cultured neonatal rat heart cells exposed to doxorubicin

Doxorubicin (Adriamycin, ADR) is an anthracycline antineoplastic with the serious side effect of dose-related cardiomyopathy. A model of ADR cardiotoxicity was created to examine some subcellular toxic effects of ADR with cultured cardiac myocytes (CMCs) exposed to 1 × 10−7 to 1 × 10−5M ADR for 24 to 48 hr. Lactate dehydrogenase (LDH) activity was monitored in the CMC medium to monitor CMC damage as a function of ADR concentration. A four- to eightfold elevation of LDH activity in medium of CMCs exposed to 1 × 10−6 to 1 × 10−5M ADR was found. No change in LDH activity was detected in medium of CMCs exposed to 1 × 10−7M ADR or in control CMCs after 24 or 48 hr ADR exposure. Data suggest a dose-dependent effect of ADR on LDH activity in CMC medium. Serial monitoring of LDH in media of ADR-exposed CMCs may correlate with other evidence of ADR cardiotoxicity in vitro.