Objective      To determine the effects of electroporation on the transfection of angiotensin Ⅱ type 2 receptor (AT2R) gene into rat carotid arteries and predict its role in neointimal hyperplasia of carotid arteries after balloon angioplasty.     Methods    After the establishment of rat carotid balloon injury restenosis model

18 SD rats were divided into AT2R transfection group

empty plasmid transfection group (GFP)

and non-transfection group (n=6). AT2R gene plasmid or empty plasmid was transfected by electroporation into rat carotid arteries. Their arteries were harvested at 3

14 and 21 d after gene transfer

with 2 rats at each time points. The expression of AT2R and morphology of the arteries were evaluated by immunohistochemistry and HE staining respectively.     Results    Electroporation-mediated transfection of AT2R gene into injured rat carotid arteries significantly up-regulated the levels of AT2R mRNA in the neointima in a time dependent manner from day 3 to day 14 (strong to moderate to mild expression). But no expression of AT2R was found in the other 2 groups at these 3 time points. At day 21

AT2R transfection significantly reduced intimal/medial area ratio as compared with non-transfection group and GFP transfection group (0.76±0.08 vs 1.39±0.08 and 1.32±0.10

P0.01). No significant difference was found between non-transfection group and GFP transfection group.     Conclusion    Our results indicate that electroporation is an effective means to introduce naked AT2R DNA into the blood vessel wall

and gene transfer of AT2R in vessel wall may effectively inhibit VSMC proliferation and neointimal hyperplasia in the rat carotid arteries after balloon angioplasty.