TAT and Patent ductus arteriosus: Here, we also tried to detect the levels of cellular ROS in the transfected PDA, and we found significant increase in cellular ROS in Tat or mortalin single-transfected groups, but the ROS levels were reduced by almost half in the cotransfected cells, compared with Tat transfection, as measured by DCFDA fluorescence stain (Fig. 7a).