The High Expression Of TRPC1 In Myocardium In Salt-sensitive Hypertension Rats And Its Effects On Myocardial Fibrosis

Objective: To investigate the effect of TRPC1 on myocardial fibrosis in salt-sensitive hypertensive rats by detecting the expression of TRPC1 in the myocardium of rats with salt-sensitive hypertension and observing the changes of myocardial structure and fibrosis.Methods: 25 seven weeks old male Wistar rats were randomly divided into normal control group(CON group)(n = 5)and high salt group(n = 20).Baseline blood pressure of each group was measured before experiment.Rats in CON group were fed with diet containing normal salt diet(0.5% Na Cl)for 13 weeks,while rats in high salt group were fed with 8% Na Cl diet,blood pressure was measured every two weeks,and the rats were raised for 8 weeks.After that,rats with systolic blood pressure greater than 10% compared with baseline blood pressure and ? 140 mm Hg were judged to be salt-sensitive hypertension(SSH)for the first time,the rats of the initial SSH were treated with low salt diet(0.3% Na Cl)for 1 week,the final blood pressure was lower than 5% of the previous group were judged as salt-sensitive hypertension group(SSH group)(n = 5),continue to feed high salt diet(8% Na Cl)for 4 weeks.While the rats in high salt group were fed with high salt diet after 8 weeks having a blood pressure increase of less than 5% compared with baseline pressure were judged as salt-resistant normotension group(SRN group)(n=5).All rats were weighed at the age of 21 weeks,and were detected by echocardiography.The heart weights and left ventricular weights were measured.The expression of TRPC1 was detected by immunohistochemical staining,the degree of fibrosis was observed by Masson staining and Western blot was used to detect TRPC1,collagen?and collagen?.Results:1,The systolic blood pressure of tail arteries in SSH group were significantly higher than that in CON group(P<0.01),but there was no significant difference between SRN group and CON group(P> 0.05),The systolic blood pressure of caudal arteries in SSH group were significantly higher than that in CON group(P<0.01).2,Compared with the CON group,the myocardial thickness and the left ventricle weight index(LVW)of SSH group increased after high-salt diet(P <0.05),and there was no significant change in myocardial thickness and the left ventricle weight index(LVW)between CON and SRN group(P> 0.05).However,compared with the SRN group,the myocardial thickness and the left ventricle weight index(LVW)of the SSH group increased significantly(P<0.05).3,Masson staining showed myocardial fibrosis increased in SSH group.4,Compared with the CON group,the expression of TRPC1 protein in the myocardium of SSH group increased significantly(P <0.01),but there was no significant difference between the SSH group and the CON group(P> 0.05);And the expression of TRPC1 protein in the myocardium of SSH group were significantly higher than that of SRN group(P <0.01).5,Compared with the CON group,the expressions of type I collagen and type III collagen in the SSH group were increased(P<0.05),and the expressions of type I collagen and type III collagen in the SRN group were not significantly different(P>0.05).Compared with the SRN group,the expressions of type I collagen and type III collagen in the SSH group increased(P<0.05).Conclusion: 1.The expression of TRPC1 in myocardial tissue of salt-sensitive hypertensive rats was increased.2.Salt-sensitive hypertensive rats have ventricular remodeling after high salinity feeding.3.Salt-resistant normotensive rats have not ventricular remodeling after high salinity feeding.