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Placental steal of myometrial blood flow in rats with unilateral oviduct ligation
Author(s) -
Reading Stacey Allan,
Fuller Robert R,
Pauyo Thierry,
Colton Ilsley B,
Osol George,
Brayden Joseph Elliot
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1422-c
During pregnancy, the maternal hormonal milieu changes to augment blood flow to the reproductive structures. A direct effect, if any, of the fetoplacental unit, or of litter size on myometrial blood flow (MBF) is not known. Thus, we used fluorescent microspheres to measure MBF in 20‐day pregnant (LP) and non‐pregnant (NP) Sprague‐Dawley rats with unilateral oviduct ligation. LP rats with and without a ligated (LIG) oviduct had 15±1 and 14±1 fetal pups, respectively, demonstrating that the single horn maintained normal litter size In LP rats, the highest blood flow was measured in the uterine horn with a LIG oviduct to prevent implantation ( n =6; 270±24 ml·100g −1 ·min −1 ). In the non‐LIG uterine horn ( n =6) that did contain fetal pups, MBF was 72±12 ml·100g −1 ·min −1 . In NP rats with a unilateral oviduct ligation, MBF was 79±27 and 98±21 ml·100g −1 ·min −1 in the LIG ( n =6) and non‐LIG ( n =6) uterine horns, respectively. We also measured MBF in surgically unmodified animals and found that pregnancy significantly (p<0.05) increased MBF from 95±23 in (NP; n =5) to 151±29 ml·100g −1 ·min −1 (LP; n =10). Thus in LP rats, MBF was highest if no fetal pups were present and lowest when a high number of pups were present. This suggests that (1) systemic hormonal factors increase MBF, (2) unilateral ligation results in a compensatory adaptive process that maintains normal litter size and placental perfusion at the expense of a significantly reduced MBF.