HMOX1 and cardiomyopathy: Considering the essential role of oxidative stress and RIPK3 in Nrf2-regulated cardiomyopathy induced by PM2.5, ROS scavenger N-acetyl-L-cysteine (NAC), HO1 activator cobalt protoporphyrin IX (CoPPIX) and RIPK3 siRNA (si-RIPK3) were subjected to PM2.5-incubated cardiomyocytes isolated from Nrf2-/- mice.