For the scratch test, cells were plated at 2×105 cells/well in a 6-well plate and grown overnight under standard conditions. After 12 h, the confluent monolayer was scratched manually with a plastic 200 μl pipette tip and after washing with PBS. Then the culture was continued in 2% serum at 37°C for 24 h. The wound area were imaged using an inverted microscope at 100× magnification. The distance was measured using ImageJ2x. (A) Images of wounds of A549 cells transfected with the indicated plasmids taken 0, 12 and 24 h afer the wounds were inflicted (× 100). (B) Overexpressing PARP1 promoted the wound-healing process in A549 cells, whereas PARP1 silencing did not contribute to wound healing. Wound-healing results for A549 cells transfected with the indicated plasmids (analyzed by t-tests). *p < 0.05; **p < 0.01;***p < 0.001.