Estrogen promotes microvascular pathology in female stroke-prone spontaneously hypertensive rats.
Estrogen produces both beneficial and adverse effects on cardiovascular health via mechanisms that remain unclear. Stroke-prone spontaneously hypertensive rats (SHRSP) maintained on Stroke-Prone Rodent Diet and 1% NaCl drinking water (starting at 8 wk of age) rapidly develop stroke and malignant nephrosclerosis that can be prevented, despite continued hypertension, by drugs targeting angiotensin II and aldosterone actions. This study evaluated estrogen's effects in the SHRSP model. Female SHRSP that were sham operated (SHAM), ovariectomized (OVX) at 4 wk of age, or OVX and treated with estradiol benzoate (E2,30 microg x kg-1 x wk-1) were studied. In a survival protocol, OVX rats lived significantly longer (15.1 +/- 0.3 wk) compared with SHAM (13.6 +/- 0.2 wk) or OVX+E2 rats (12.4 +/- 0.2 wk). In a protocol in which animals were matched for age, at 11.5 wk, terminal systolic blood pressure and urine protein excretion were elevated in SHAM and OVX+E2 rats compared with OVX rats; blood urea nitrogen, renal microvascular and glomerular lesions, and plasma renin concentration were elevated in OVX+E2 relative to SHAM or OVX rats. In a survival protocol using intact female SHRSP, treatment with an antiestrogen (tamoxifen, 7 mg.kg-1.wk-1) prolonged survival by >2 wk compared with controls (P < 0.01). The data indicate that estrogen promotes microangiopathy in the kidney and stroke in saline-drinking SHRSP.
Stier
Charles T
CT
Department of Pharmacology, New York Medical College, Valhalla 10595, USA. charles_stier@nymc.edu
Chander
Praveen N
PN
Rosenfeld
Louis
L
Powers
C Andrew
CA
D000803:Angiotensin I / Q000097:blood; D000818:Animals; D001794:Blood Pressure / Q000235:genetics / Q000502:physiology; D001835:Body Weight / Q000235:genetics; D002196:Capillaries / Q000187:drug effects / Q000254:growth & development; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D015914:Estrogen Replacement Therapy; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D007668:Kidney / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000139:chemically induced* / Q000473:pathology; D009929:Organ Size / Q000235:genetics; D010052:Ovariectomy; D051381:Rats; D011918:Rats, Inbred SHR; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors; D012083:Renin / Q000097:blood; D012965:Sodium Chloride; D013268:Stimulation, Chemical; D020521:Stroke / Q000235:genetics* / Q000473:pathology*; D016019:Survival Analysis; D013629:Tamoxifen / Q000494:pharmacology
D004965:Estrogen Antagonists; D004967:Estrogens; D011960:Receptors, Estrogen; D013629:Tamoxifen; C074283:estradiol 3-benzoate; D012965:Sodium Chloride; D004958:Estradiol; D000803:Angiotensin I; D012083:Renin