BACKGROUNDS: Thermal ablation has been widely used to manage liver tumor. This study was designed to determine histological change of rat liver after microwave ablation, investigate the effect of microwave ablation on gene transfection.METHODS: In this study, microwave ablation was applied to rat liver, tissue demarcation was evaluated. Green fluorescent protein (GFP) and Renilla luciferase-expressing plasmids were administrated to the liver by percutaneous or intravenous injection pre-ablation. The expression of transgene in the reactive inflammatory zone was evaluated. GFP expression was determined with the inverted fluorescence microscope in frozen section, and Renilla luciferase expression in target tissue was determined using Renilla luciferase plasmid kit. The effect of hydrodynamic portal vein injection was also evaluated.RESULTS: GFP expression was observed in the tissue of reactive inflammatory zone after microwave ablation and plasmid injection. Green fluorescence in targeted area was visible on till the seventh day post ablation under inverted fluorescence microscope. On the first day postablation and Renilla luciferase plasmid injection, luminescence value of the experimental group was higher than the control group, but lower than the portal hypertension injection group.CONCLUSIONS: Direct injection of plasmid vector to inflammatory reaction zone after microwave ablation can achieve effective gene transfection, but the transfection efficiency is lower than hydrodynamic portal injection. These results provide some experimental basis for exploring microwave ablation assistant target gene transfer for cancer gene therapy.