title: [An experimental study of expression of angiotension converting enzyme 2 in myocardium and effect of telmisartan treatment in pressure-overloaded rats].
abstract: OBJECTIVE
  To study the effect of hypertension and telmisartan treatment on the protein and gene expression of cardiac angiotensin-converting enzyme 2 (ACE2) in pressure-overloaded rats.
  
  
  METHODS
  Coarctation of suprarenal abdominal aorta was reproduced in 8 week-old male Sprague-Dawley (SD) rats and then randomized into 4 groups, including a sham group (n=15), a suprarenal aortic coarctation group (model group, n=12), a suprarenal aortic coarctation with low-dose Telmisartan treatment group (low-dose group, 2 mgxkg(-1)xd(-1), n=11) and a suprarenal aortic coarctation with high-dose Telmisartan treatment group(high-dose group, 10 mgxkg(-1)xd(-1), n=13). Telmisartan or equivalent amount of normal saline was gavaged 24 hours before the operation and once every day afterwards for 3 weeks. At the end of 3 weeks, the concentrations of angiotensin (AngII) in plasma and myocardium were measured by radioimmunoassay. Changes in both protein quantity and gene expressions of both ACE2 and ACE were determined by Western blotting analysis and reverse transcription-polymerase chain reaction (RT-PCR) technique, respectively.
  
  
  RESULTS
  Suprarenal abdominal aortic coarctation induced a significant increase in the plasma and myocardium AngII concentration [plasma: (495.1+/-55.6) ng/L vs. (269.2+/-39.5)ng/L, myocardium: (103.6+/-23.7) ng/g vs. (49.5+/-13.5) ng/g, both P<0.01] and expressions of gene and protein of ACE (P<0.01) and ACE2 (P<0.05). Telmisartan further increased the concentration of AngII in plasma and myocardium in a dose-dependent manner [plasma: (702.2+/-40.6) ng/L vs. (612.6+/-35.5) ng/L, myocardium (211.5+/-21.5) ng/g vs. (189.6+/-43.6) ng/g, both P<0.05], and induced a dose-dependent increase in both protein and gene expression of ACE2 (protein 1.16+/-0.06 vs. 0.79+/-0.04, gene 0.54+/-0.08 vs. 0.41+/-0.04, both P<0.05). Expression of ACE2 protein in low-dose and high-dose groups was increased by 1.0 and 1.58 folds respectively, and gene was increased by 1.3 and 1.6 folds (all P<0.05). The expression of ACE protein and gene in model group increased significantly (protein: 2.10+/-1.07 vs. 1.02+/-0.05, gene: 1.93+/-0.09 vs. 0.26+/-0.09, both P<0.01). Telmisartan had no significant effect on ACE gene and protein expressions (both P>0.05).
  
  
  CONCLUSIONS
  Suprarenal abdominal aortic coarctation induced a significant increases of ACE and ACE2 gene and protein expressions. Telmisartan induces a dose-dependent increases of cardiac ACE2 gene and protein expression,which may be the mechanism of its therapeutic effects.
authors.affiliation: Department of Cardiology, The Affiliated Baoan Hospital of Nanfang Medical University, Shenzhen 518101, Guangdong, China. wang.j63@163.com
authors.forename: Li-jun
authors.initials: LJ
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Ma
authors.forename: Xin-xue
authors.initials: XX
authors.lastname: Liao
authors.forename: Jian-gui
authors.initials: JG
authors.lastname: He
authors.forename: Wen-wu
authors.initials: WW
authors.lastname: Zhang
authors.forename: Fang
authors.initials: F
authors.lastname: Tian
authors.forename: Yi-ming
authors.initials: YM
authors.lastname: Cai
authors.forename: Hai-bo
authors.initials: HB
authors.lastname: Gu
authors.forename: Yan-hua
authors.initials: YH
authors.lastname: Hao
authors.forename: Xue-song
authors.initials: XS
authors.lastname: Hu
authors.forename: Hong-mei
authors.initials: HM
authors.lastname: Zou
authors.forename: Qiu-ling
authors.initials: QL
authors.lastname: Zhou
mesh_terms: D000804:Angiotensin II / Q000378:metabolism; D000085962:Angiotensin-Converting Enzyme 2; D000818:Animals; D001017:Aortic Coarctation / Q000188:drug therapy / Q000378:metabolism*; D001562:Benzimidazoles / Q000494:pharmacology*; D001565:Benzoates / Q000494:pharmacology*; D004195:Disease Models, Animal; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077333:Telmisartan
chemical_list: D001562:Benzimidazoles; D001565:Benzoates; D012333:RNA, Messenger; D000804:Angiotensin II; D007703:Peptidyl-Dipeptidase A; C000705329:Ace2 protein, rat; D000085962:Angiotensin-Converting Enzyme 2; D000077333:Telmisartan