| Popis: |
Objective To investigate the role and mechanism of sphingosine-1-phosphate type 1 receptor (S1PR1) in neointimal hyperplasia after carotid artery injury in mice. Methods A total of 40 C57BL/6 mice were randomly and equally subjected to 4 groups: sham operation+AAV-LacZ group, sham operation+AAV-S1PR1 group, model+AAV-LacZ group, and model+AAV-S1PR1 group. In 2 weeks after the delivery of AAV-LacZ or AAV-S1PR1 adenovirus to corresponding mice via tail vein injection, a mouse model of carotid artery injury was established with a flexible wire inserting into the common carotid artery. After 4 weeks, the carotid artery was harvested to measure the severity of neointimal hyperplasia by HE staining, the expression of α-smooth muscle actin (α-SMA) by immunofluorescence staining, and the levels of proliferating cell nuclear antigen (PCNA) and interleukin-6 (IL-6) by immunohistochemistry. In the isolated and primarily cultured mouse aortic vascular smooth muscle cells (VSMCs), the adenovirus Ad-S1PR1 or Ad-LacZ were transfected respectively, and then the cells were incubated with 1 μmol/L S1P. The hallmarks of phenotypic switch of VSMCs were detected with Western blotting and immunofluorescence assay, cell proliferation with EdU staining, migration by scratch wound healing assay and transwell migration assay, and activation of IL-6/STAT3 pathway by Western blotting. Results In 4 weeks after model establishment, the mice of the model+AAV-LacZ group had obvious neointimal hyperplasia, phenotypic switch and cell proliferation (P < 0.05), and significant upregulation of IL-6 in the carotid artery injury when compared with the mice of the sham operation+AAV-LacZ group. In the mice of the model+AAV-S1PR1 group, the level of S1PR1 was over-expressed (P < 0.05), and above phenomena were aggravated when compared with the mice from the model+AAV-LacZ group (P < 0.05). In the in vitro study, S1P treatment induced the phenotypic switch, proliferation and migration, and activation of the IL-6/ STAT3 pathway in the primary VSMCs (P < 0.05), and the pathophysiological changes above were further aggravated after the transfection of Ad-S1PR1 (P < 0.05). Conclusion S1P/S1PR1 can promote the phenotypic switch and proliferation and migration of VSMCs, and aggravate the intimal hyperplasia after vascular injury, which may be due to the activation of IL-6/STAT3 pathway. |
