ABSTRACT
Objective To investigate the relationship between angiotensin Ⅱ ( AngⅡ) and transformation of vascular fibroblasts phenotype .Methods Eighteen rats were randomly assigned into the untreated group , mini-pump infusion of saline group and mini-pump infusion of AngⅡgroup which was used as the hypertension model .Their systolic pressure and vascular morphology were examined .The expression of catalase ( CAT ) and 4HNE was examined by immunohistochemistry .Western blotting was used to examine the expression of CAT of adventitial fibroblasts which were cultured by different incubation times and concentrations of Ang Ⅱ.Results Compared with untreated and mini-pump infusion of saline groups , the systolic pressure and carotid media thickness stained by HE of mini-pump infusion of AngⅡgroup were significantly higher (P<0.01).The results of immunohistochemistry showed that the expression of CAT ofAngⅡgroup was significantly lower than that of untreated group , however the expression of 4HNE of AngⅡgroupwas higher than that of untreated group (P<0.05).Furthermore, the results of Western blotting indicated that the effect of Ang Ⅱ on down-regulation of CAT function was in a dose and incubation time dependent manner .Conclusion AngⅡdown-regulates adventitial CAT expression and promotes fibroblasts phenotypic transformation which leads to pathological arterial vascular remodeling .
ABSTRACT
AIM:To explore the effect of extracellular signal-regulated kinase 1/2 ( ERK1/2) on the vascular adventitial remodeling in a hypertension rat model .METHODS:The rats were randomly divided into control group , mini-pump infusion of saline group and mini-pump infusion of angiotensin II ( Ang II) group as the hypertension model .The sys-tolic pressure and vascular morphology of the rats were examined .Adventitial fibroblasts were treated with Ang II , PD98059 ( ERK1/2 inhibitor) and Ang II+PD98059.The catalase ( CAT) expression in the cells was detected by Western blotting . RESULTS:Compared with control group and mini-pump infusion of saline group , the systolic pressure and carotid media thickness (stained by HE) in mini-pump infusion of Ang II group were significantly increased (P<0.01).Meanwhile, ar-tery morphology in mini-pump infusion of Ang II group had obviously changed with a significant occurrence of pathological vascular remodeling .The result of Western blotting showed that the expression of CAT in the adventitial fibroblasts treated with Ang II+PD98059 was much higher than that in the cells treated with Ang II alone (P<0.05), indicating that down-regulation of CAT induced by Ang II was restored by ERK 1/2 signaling pathway .CONCLUSION:Ang II down-regulates CAT through ERK1/2 pathway and promotes cell phenotype transformation , which lead to pathological vascular remodeling .