Role Of Steroid Receptor Coactivator 1 In Angiotensin ?-Induced Hypertension Vascular Remodeling In Mice

Research BackgroundSteroid receptor coactivator-1(SRC-1)is a member of the SRC family which functions as a transcriptional coactivator for nuclear receptors and other transcription factors,and enhance its transcriptional activity.Multiple physiological roles of SRC-1 have been revealed,SRC-1 may be involved in the proliferation and invasion of breast cancer,prostate cancer,liver cancer and Hepatocellular Carcinoma.SRC-1 exert much regulation in many physiological processes such as synaptic plasticity and stem cells differentiation.In addition,SRC-1 gene knockout can weaken the protective effect of estrogen on vascular injury,thus aggravating the neointimal formation after vascular injury.Although previous studies showed that SRC-1 in the cardiovascular system of endothelial cells,vascular smooth muscle cells and myocardial cells were expressed,however,it is not clear whether SRC-1 can regulate vascular remodeling induced by Ang ?.High blood pressure(Hypertension)refers to the systemic arterial blood pressure increased as the main feature,clinical with heart,brain and kidney,organ functional or organic damage syndrome.The process of vascular remodeling in hypertension is related to cell apoptosis,inflammatory reaction and fibrosis process.How to regulate vascular remodeling after hypertension is a hot research topic ObjectivesTo investigate the role of SRC-1 in vascular remodeling in Ang ?-induced hypertensive miceMethods1.According to the requirements of the experimental animals to acquire SPF C57/male SRC-1 knockout mice(SRC-1-/-mice)and healthy male wild,type mice.All experiments were performed using 8-10 weeks old male mice,the body weight in18-20g.Through the selection of gene identification in accordance with experimental conditions in mice.The model of hypertension was established by subcutaneous embedding of angiotensin ? micro osmotic pump under aseptic conditions.Randomly divided into angiotensin ? group and saline group2.Determination of blood pressure in mice with noninvasive arterial blood pressure instrument with BP98A;Cardiac ultrasonography to detect changes in cardiac function;mice were observed in the membrane thickness of thoracic aortic HE staining(MT),the lumen(LD),and MT/LD ratio was calculated;changes of collagen content in mice were observed after vascular Masson staining;real-time fluorescence quantitative PCR method to detect groups of mice in the vascular tissue IL-1 beta,TNF-alpha,expression level of mRNAResults1?Identification results of SRC-1 gene knockout.The results showed:SRC-1-/-gene knockout(KO)mice,only one of 680 bp bands;wild type(WT)mice,only one of 300 bp bands;heterozygous mice(SRC-1+/-),contains two bands,680 bp bands and 300 bp bands.2?After the successful use of angiotensin ? induced hypertension model,the changes of the tail artery systolic pressure in each group were measured by a small animal noninvasive blood pressure SoftronBP98A,The results showed:There was no significant difference in the systolic blood pressure(SBP)between the two groups of Ang ? and the NS groups;there was a significant difference between the two groups of Ang ? and the NS group.The systolic blood pressure(153.2 ± 6.0mmHg;153.0 ±9.0mmHg)in the two groups of Ang ? was significantly higher than the two groups of NS group(113.7 ± 3.0mmHg;113.7± 8.5mmHg)(P<0.01);3?After HE staining,we observed and measured the thickness of the aorta,the diameter of the lumen,and the ratio of the thickness of the vascular lumen and the lumen of the vessel.The results showed:Compared with WT + NS group,the ratio of intima-media thickness and mid-wall thickness and luminal diameter(MT/LD)of the thoracic aorta in the WT+ Ang ? group were significantly increased.(p<0.05)Compared with theWT+ Ang ? group,the ratio of intima-media thickness and midmut thickness and luminal diameter(MT/LD)of the thoracic aorta in the KO+ Ang ? group was also significantly higher.(p<0.05)4?After Masson staining,the changes of collagen fiber content in each group of mice were observed and measured.The results showed:Compared with the WT + NS group,the collagen content of the thoracic aorta of the WT + Ang ? group was significantly increased(p<0.05).Compared with the WT+ Ang ? group,the collagen content of the thoracic aorta of the KO + Ang ? group was significantly increased(p<0.05).5?Real time fluorescent quantitative detection of TNF-alpha,IL-1 beta mRNA expression level.The results showed:Compared with WT + NS group and KO + NS group,the mRNA expression of TNF-?,IL-1? in the thoracic aorta was notsignificantly different.Compared with WT + Ang ? group and KO + Ang ? group,the expression of TNF-?,IL-1? mRNA in the thoracic aorta was significantly higher in KO + Ang ? group?Conclution1?SRC-1 gene knockout can enhance the vascular remodeling in hypertension induced by angiotensin ??2?SRC-1 gene knockout can enhance the expression of TNF-and IL-1 in the process of angiotensin ? induced hypertension.