HMOX1 and diabetic cardiomyopathy: In this study, diabetic cardiomyopathy model in rats was duplicated, and Phase II enzyme inducer CPDT, as intervention agent, was used to detect relevant indicators, such as miR-503 and Nrf2/ARE signaling pathway, including Nrf2, HO-1 and MDA, to investigate whether the Phase II enzyme inducer (CPDT) reduces myocardial cell apoptosis, reduces the occurrence and development of diabetic cardiomyopathy through miR-503 and Nrf2/ARE signaling pathway, and provides new therapeutic targets for diabetic cardiomyopathy.