Influence Of Urocortin On Rat’s VSMC Transdifferentiation And The Secretion Of Extracellular Matrix Induced By Angiotensin Ⅱ In Vitro

Abstract:objective To explore the influence of Urocortin (Ucn) on neonatal rat’s vascular smooth muscle cells (VSMC) transdifferentiation and the secretion of extracellular matrix induced by angiotensionⅡ(AngⅡ). Methods:The VSMC were isolated and sub-cultured. Experiments had been performed after the cells were prepared 2×105/ml suspension with DMEM and cultured in 6-well plates. The cells were divided into four groups according to the different intervention factors, final concentration of Ucn was 10-7 mol/L.and AngⅡwas 10-6mol/L①control group:the VSMC were cultured without any intervention factor;②AngⅡgroup:the VSMC were stimulated by AngⅡ;③Ucn group: the VSMC were stimulated by Ucn;④AngⅡ+Ucn group:the VSMC were co-stimulated by AngⅡand Ucn. The VSMC were cultured for 24h,48h. (1) The expressions ofα-SMA was detected by immunocytochemistry method. (2) The influence of Ucn on VSMC proliferation was determined by MTT assay. (3)The content of ColⅠand OPN in the cultured supernatant were measured by ELISA. Results: (1) The change of expressions ofα-SMA of rat’s VSMC:The expressions ofα-SMA in rat’s VSMC cultured for 24h,48h, compared with expressions ofα-SMA of control group were no significant change, Ucn group was similar with control group, expressions of a-SMA were no significant change; AngⅡgroup increased from 24h than that of control group at the same time (P>0.05), cultured for 48h, AngⅡgroup increased significantly than that of control group (P<0.05), AngⅡ+Ucn group decreased than that of AngⅡgroup at the same time (P<0.05):(2) Influence on the expressions of ColⅠand OPN:cultured for 48h, the expressions of ColⅠand OPN of AngⅡgroup more obviously increased than that of control group (P<0.05); AngⅡ+Ucn group significantly decreased the expressions of ColⅠand OPN, compared with AngⅡgroup (P<0.05).(3)Influence on L-type calcim channel:UCN inhibited the viability of VSMC in a concentration-dependent manner and markedly reduced the increase of the viability of VSMC pretreated by L-type calcim channel agonist Bay K8644,in contrast to AngⅡgroup(P<0.05).conclusion:(1) Urocortin can inhibit AngⅡ-induced rat’s vascular smooth muscle cells transdifferentiation. (2) Urocortin can decrease the secretion of ColⅠand OPN induced by AngⅡ. (3) Urocortin could inhibit the viability of vascular smooth muscle cells by blocking L-type calcium channels in a concentration-dependent manner.