MAPK8 and hydrops fetalis: Furthermore, the pre‐treatment of cells with Mito‐TEMPO significantly alleviated the generation of ROS; however, the JNK inhibitor (SP600125) and caspase 3 inhibitor (z‐DEVD‐FMK) failed to induce change in the increased level of ROS in response to HF, indicating that ROS production occurs upstream of JNK and caspase activation (Figure 4E, F).