Losartan attenuates vascular remodeling of the aorta in spontaneously hypertensive rats and the underlying mechanism.
OBJECTIVE
To determine the effect of losartan on vascular remodeling and the underlying mechanism in spontaneously hypertensive rats(SHR).


METHODS
SHR of 12 weeks old were given losartan orally [0, 15, 30 mg/(kg.d), n=12]. The tail arterial pressure was measured every week. Eight weeks later, the pathological changes and p22(phox) expression in the thoracic aorta, the activity of catalase (CAT), the contents of H(2)O(2) and Ang II in the plasma were evaluated.


RESULTS
Blood pressure was increased in the SHR accompanied by the thickened wall and increased p22(phox) expression in the thoracic aorta. The plasma levels of H(2)O(2) and Ang II were elevated while the CAT level was decreased in the SHR. Administration of losartan reversed the thickened wall and increased the CAT activity concomitantly with the decreased plasma levels of H(2)O(2) and p22(phox) expression in the SHR. The plasma level of Ang II increased after the losartan treatment.


CONCLUSIONS
Oxidative stress induces the vascular remodeling of the aorta in the SHR. Losartan can reverse the vascular remodeling through down-regulating p22(phox) expression and inhibiting the oxidative stress.
Li
Fangxiong
F
Department of Cardiology, Xiangya Hospital, Central South University, Changsha 410008, China.
Shi
Ruizheng
R
Liao
Meichun
M
Li
Jianzhe
J
Li
Shixun
S
Pan
Wei
W
Yang
Tianlun
T
Zhang
Guogang
G
D000804:Angiotensin II / Q000097:blood; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001011:Aorta / Q000473:pathology* / Q000503:physiopathology; D002374:Catalase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000097:blood; D006973:Hypertension / Q000188:drug therapy* / Q000473:pathology* / Q000503:physiopathology; D019808:Losartan / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D019255:NADPH Oxidases / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D000959:Antihypertensive Agents; D000804:Angiotensin II; D006861:Hydrogen Peroxide; D002374:Catalase; D019255:NADPH Oxidases; C515768:Cyba protein, rat; D019808:Losartan