Valsartan but not atenolol improves vascular pathology in diabetic Ren-2 rat retina.
Am J Hypertens
; 20(4): 423-30, 2007 Apr.
Article
em En
| MEDLINE
| ID: mdl-17386351
ABSTRACT
BACKGROUND:
To determine whether angiotensin type 1 receptor blockade (AT1-RB) or antihypertensive therapy per se, attenuates acellular capillaries and proliferating endothelial cells in the retina of diabetic Ren-2 rats.METHODS:
Eight-week-old hypertensive Ren-2 rats were made diabetic (streptozotocin, 55 mg/kg) or nondiabetic (0.1 mol/L citrate buffer) and studied for 20 weeks. Diabetic Ren-2 rats received by gavage the AT1-RB valsartan at 4, 10, or 40 mg/kg/d or the beta1-adrenergic receptor blocker atenolol at 30 mg/kg/d. Systolic blood pressure (BP) was measured every 4 weeks. Acellular capillaries (devoid of pericytes and endothelial cells) were counted on trypsin digests. Proliferating endothelial cells were evaluated using double immunolabeling for isolectin and proliferating cell nuclear antigen.RESULTS:
Systolic BP was unchanged in control Ren-2 rats throughout the study (186.6 +/- 3.5 mm Hg, nondiabetic; 185.0 +/- 0.7 mm Hg, diabetic; week 20). In diabetic Ren-2 rats, 4 and 10 mg of valsartan and atenolol reduced systolic BP to a similar extent, and at 20 weeks were comparable to diabetic Sprague Dawley rats (123.0 +/- 1.4 mm Hg). In diabetic Ren-2 rats, 40 mg of valsartan reduced systolic BP (110.9 +/- 1.1 mm Hg, 20 weeks) below that of Sprague Dawley rats. Acellular capillaries and proliferating endothelial cells were increased by 3- and 1.6-fold, respectively, in diabetic Ren-2 controls and reduced with 4 and 10 mg of valsartan and further reduced with 40 mg of valsartan. Atenolol had no effect on retinal pathology in diabetic Ren-2 rats.CONCLUSIONS:
Blockade of the renin-angiotensin system but not antihypertensive therapy with atenolol reduces vascular pathology in diabetic Ren-2 retina, suggesting that angiotensin II is a causative factor and therapeutic target in diabetic retinopathy.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vasos Retinianos
/
Atenolol
/
Tetrazóis
/
Valina
/
Renina
/
Antagonistas Adrenérgicos beta
/
Bloqueadores do Receptor Tipo 1 de Angiotensina II
/
Retinopatia Diabética
Limite:
Animals
Idioma:
En
Revista:
Am J Hypertens
Assunto da revista:
ANGIOLOGIA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Austrália