AimTo investigate the alteration of expression of calcineurin in the abdominal aortas and levels of inflammatory cytokines injured by balloon in rats.MethodsFourty-eight healthy adult male SD rats were randomly divided into two groups: sham group (n=24) and balloon group (n=24).Thirty days after injury, specimens were obtained from rats.HE staining and immunohistochemistry were performed to measure the expression level of CaN in arterial wall.Pathological changes of the arterial wall were observed by light microscope.The serum concentrations of MCP-1 was determined by Elisa.ResultsIntimal hyperplasia was observed in balloon injured rats, the neointima was not uniform in thickness.The thickness of the intimal layers, and the ratio of the intimal and the medial layers in the sham group was obviously lower than that in the balloon group (P<0.05).Immunohistochemistry assay showed that the expression of CaN was significantly increased in balloon group compared with that in the sham group (P<0.05).The serum concentrations of MCP-1 in balloon group is higher than that in sham group (P<0.05).ConclusionsIntimal hyperplasia in rat abdominal aorta following balloon injury, accompanied by the expression of CaN protein and plasma inflammatory cytokines MCP-1 levels were significantly increased，which indicated that CaN signaling pathway and MCP-1 may play an important role in intimal hyperplasia caused by balloon injury.