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The Effect of Ovariectomy and Estrogen on Penetrating Brain Arterioles and Blood‐Brain Barrier Permeability
Author(s) -
Cipolla Marilyn J.,
Godfrey Julie A.,
Wiegman Marchien J.
Publication year - 2009
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.3109/10739680903164131
Subject(s) - ovariectomized rat , estrogen , endocrinology , medicine , ctl* , evans blue , blood–brain barrier , chemistry , lucifer yellow , transcellular , in vitro , gap junction , central nervous system , biochemistry , intracellular , cytotoxic t cell
Objective : We investigated the effect of estrogen replacement on the structure and function of penetrating brain arterioles (PA) and blood‐brain barrier (BBB) permeability. Materials and Methods : Female ovariectomized Sprague‐Dawley rats were replaced with estradiol (E 2 ) and estriol (E 3 ) (OVX + E; N =13) and compared to ovariectomized animals without replacement (OVX; N =14) and intact controls (CTL, proestrous; N =13). Passive and active diameters, percent tone, and passive distensibility of pressurized PA were compared. In addition, BBB permeability to Lucifer Yellow, a marker of transcellular transport, was compared in cerebral arteries. Results : Ovariectomy increased myogenic tone in PA, compared to CTL, that was not ameliorated by estrogen treatment. Percent tone at 75 mmHg for CTL vs. OVX and OVX + E was 44±3% vs. 51±1% and 54±3% ( P <0.01 vs. CTL for both). No differences were found in passive diameters or distensibility between the groups. BBB permeability increased 500% in OVX vs. CTL animals; however, estrogen replacement restored barrier properties: flux of Lucifer Yellow for CTL, OVX, and OVX + E was (ng/mL): 3.4±1.2, 20.2±5.3 ( P <0.01 vs. CTL), and 6.15±1.2 (n.s.). Conclusions : These results suggest that estrogen replacement may not be beneficial for small‐vessel disease in the brain, but may limit BBB disruption and edema under conditions that cause it.