Role of ORAI1 in the balloon injury-induced rat carotid artery neointimal formation and the relationship between ORAI1 and sodium and calcium exchange 1

Abstract

Objective: To investigate the role of ORAI1 in the balloon injury-induced rat carotid artery neointimal formation and the relationship between ORAI1 and sodium and calcium exchanger(NCX)1. Methods: According to condition of carotid artery balloon injury and observation time, Sprague Dawley rats were divided into 3 groups including sham group, 7 days injury group, and 14 day injury group(n=3 each). According to virus of transfection, Sprague Dawley rats were divided into 2 groups including negative control group (negative lentiviruses particles transfection after establishment of carotid artery balloon injury model, n=3) and siORAI1 group(siORAI1 transfection after operation, n=3). Carotid artery neointimal formation was analyzed after HE staining. The ORAI mRNA expression level was detected using real-time PCR. The proliferating cell nuclear antigen (PCNA), ORAI and NCX1 protein expression level were measured by Western blot. Results: (1) Carotid artery intima was significantly thicker in 7 days and 14 days injury group than in sham group((0.54±0.11)μm2 and (0.89±0.12)μm2 vs.(0.11±0.08)μm2, both P<0.05). Relative expression level of PCNA protein was significantly higher in 7 days and 14 days injury group than in sham group(1.43±0.16 and 1.95±0.16 vs. 1, both P<0.05). Relative mRNA expression level of ORAI1 (1.39±0.14 and 1.78±0.21 vs. 0.56±0.09, both P<0.05) and protein expression level (1.42±0.19 and 1.78±0.22 vs. 1, both P<0.05) were significantly higher in 7 days and 14 days injury group than in sham group.(2) After 14 days, relative expression level of ORAI1 protein was significantly lower in siORAI1 group than in negative control group (0.21±0.161, P<0.05). Carotid artery intima thickness was significantly reduced in siORAI1 group compared to negative control group((0.19±0.14)μm2 vs.(0.91±0.23)μm2,P<0.05). Relative expression level of NCX1 protein was also significantly lower in siORAI1 group than in negative control group(0.53±0.131, P<0.05). Conclusions: ORAI1 may play a key role in the balloon injury-induced neointimal formation and vascular smooth muscle cells proliferation in rat carotid artery.ORAI1 knockdown could down regulate the NCX1 expression and attenuate the balloon injury-induced neointimal formation and vascular smooth muscle cells proliferation in rat carotid artery.