Interestingly, the regulation of U50488H on the Ca2+-SERCA2a homeostasis was inhibited with the application of Nrf2 antagonist, demonstrating that the protective effect of U50488H on the myocardium in HF rats is dependent on activating the Nrf2/HO-1 pathway to regulate Ca2+-SERCA2a and to relieve the ERS response in myocardial cells. The gene discussed is HMOX1; the disease is hydrops fetalis.