Abstract: Objective To investegate the role of calcineurin (CaN) and its downstream nuclear factor of activated T-cells (NFATc3) in abdominal aorta restenosis following balloon dilatation in rats. Methods SD rats were randomly divided into sham-operated group, balloon group and cyclosporine A (CsA) group. The rats in the latter two groups were subjected to abdominal aorta injury with balloon dilatation, and those in CsA group were treated with CsA at the daily dose of 12.5 mg/kg from 3 days before the surgery to the end of the experiment. Thirty days afer the injury, histological analysis of the arterial wall was carried out with HE staining and immunohistochemistry. The expressions of CaN and NFATc3 in the abdominal aortas were detected with rea1-time PCR, and serum concentration of MCP-1 was determined using enzyme-linked immunosorbent assay. Results Intimal hyperplasia with irregular thickness of the neointima was observed in the aorta of rats with ballon injury. In rats with CsA treatment, the area of the intimal layers and the ratio of the intimal to the medial layers were obviously lower than those in the balloon injury group (P<0.05). Compared to those in the sham-operated group, the expressions of calcineurin protein and mRNA and NFATc3 mRNA in the arterial wall and serum level of MCP-1 increased significantly in the ballon injury group (P<0.05). CsA treatment significantly suppressed aorta restenosis and the alterations of CaN, NFATc3 and serum MCP-1 induced by ballon dilatation (P<0.05). Conclusions CaN-NFATc3 signal transduction pathway mediates restenosis of rat abdominal aorta following ballon dilatation, and CsA can attenuate the restenosis by suppressing this pathway.