e0037 Effects of enalapril and irbesartan on aorta remodelling and ion pumps in renovascular hypertensive rats

Objective To investigate the effects of single-drug or combination therapy of enalapril and irbesartan on aorta remodelling and its mechanisms. Methods Renovascular hypertensive rats (RHD) induced by two-kidney one-clip method were treated with normal saline (model group, n=6), enalapril [10 mg/ (kg d), n=6], irbesartan [50 mg/ (kg·d), n=6] and enalapril+irbesartan [5 mg/ (kg d)+25 mg/ (kg d), n=6] for 6 weeks. Six sham-operated rats were used as controls. Aortic morphology and structural changes in the media were observed by HE staining, immunohistochemistry and Masson staining. The content of Angiotensin II (Ang II) was measured by radioimmunoassay. The activities and mRNA levels of Na + pump and Ca 2+ pump in aortic media were determined by enzyme assay and real-time PCR respectively. Results The media area of aorta and the Ang II content were significantly increased in model group, while the activities and the mRNA levels of Na + pump and Ca 2+ pump in aortic media were obviously decreased, and Na + pump and Ca 2+ activities were increased in enalapril group and irbesartan group (p 1 -subunit and plasma membrane calcium pump isoform 1 (PMCA1) in aorta smooth muscle tissue were significantly increased in enalapril group (p + pump and Ca 2+ pump activities, media area and thickness in combination group was significantly better than single-drug intervened group (p Conclusion The amelioration of aorta remodelling induced by enalapril and irbesartan may be associated with the increase of Na + pump and Ca 2+ pump activities. There may be some synergistic effects on ameliorating of Na + pump and Ca 2+ pump activities and aorta remodelling from combination of the two drugs. The effect of enalapril on Na + pump and Ca 2+ pump activities may be mediated by increasing their mRNA expression.