| Background:Percutaneous transluminal coronary intervention (PCI) is now one of the main therapeutic measures in coronary artery atherosclerotic heart disease. However, the high incidence of post-angioplasty restenosis (RS) has not been solved yet. So to interpret the pathogenesis and find new therapy methodof RS is currently difficult point and a hot subject in the research area of cardiovascular pharmacology. Gap junction is an important pathway which allows the exchange of inorganic ion, small molecules (<1 kDa) and metabolites between adjacent cells. Studies have shown that gap junction is distributed in vascular wall widly and can accept the internal and external stimuli to overall reaction. Connexin remodeling has been acknowledged to be a molecular pathological basis of vascular diseases. We supposed that Cx43 remodeling may be involved in the process of restenosis and RNAi silencing Cx43 gene may effectively decrease vascular restenosis, which could provide a theory and target for precaution and treatment of RS.Objective:To investigate the relationship between Cx43 remodeling and restenosis. To examine the effect of silencing Cx43 gene by RNAi(ribonucleic acid interfering, RNAi)on the inhibition of the restenosis in vivo, which will provide a theoretical basis for the development of a new DNA-containing stent for the treatment of RS.Methods:Twenty-four Sprague-Dawley (SD) rats were randomly assigned into four groups (n=6):control group, injury group, Cx43-RNAi-LV-treated group and NC-GFP-LV group. Except the control group, the other three groups were injuried by balloon distension in the left common carotid arteries, then were infected with 100μL physiological saline, Cx43-RNAi-LV, NC-GFP-LV for lh at 37℃, respectively. The titer of lentivirus was 5×10 TU/mL. All rats were sacrificed at 28d after balloon injury. To observe the effect of lentivirus infected arteries by fluorescence measurement, to determine the vascular morphometric by hematoxylin-eosin staining, to examine the distribution of Cx43 protein by immunohistochemistry, to test the expression of Cx43 protein by Western blotting.Results:The fluorescence was not found in control and injury group, while it was strongly expressed in neointimal and medial area in Cx43-RNAi-LV-treated and NC-GFP-LV group. The results indicated that balloon-injury rat carotid arteries were infected with lentivirus successfully.HE staining showed that the neointima area and the ratio of neointima area /media area (NA/MA) of carotid arteries were significantly increased in injury and NC-GFP-LV group at 28 days after balloon injury compared with that in control group(P<0.01). The results suggested that the model of restenosis was successful. Compared with injury group, the neointima area and the ratio of NA/MA of carotid arteries were significantly reduced in Cx43-RNAi-LV-treated group (P<0.05). The results indicated that Cx43-RNAi-LV can significantly inhibit the vascular restenosis.The results showed that Cx43 labeling was found in media zone in all groups by using immunohistochemical analysis. A significantly strong immunostaining of Cx43 labeling was found in neointima in injury and NC-GFP-LV group, while the staining in Cx43-RNAi-LV-treated group was down-regulated in neointima. The results suggested that Cx43 remodeling may be involved in the process of vascular restenosis.Western blotting detection showed that compared with control group, the expression of Cx43 protein was significantly increased in injury and NC-GFP-LV group (P<0.01). Compared with injury group, the Cx43 protein expression was significantly decreased in Cx43-RNAi-LV-treated group (P< 0.05). The results showed that siRNA induced Cx43 silencing can inhibit the high expression of Cx43 protein in vivo.Conclusions: ①Cx43 protein remodeling involved in the process of restenosis;②RNAi silencing Cx43 gene can significantly inhibit the high expression of Cx43 protein induced by balloon injury;③RNAi silencing Cx43 gene can effectively decrease vascular restenosis induced by balloon injury. |
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