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Updated: Jun 11, 2026

Fetal Mouse Cardiovascular Imaging Using a High-frequency Ultrasound (30/45MHZ) System
Published on: May 5, 2018
Fetal-placental hypoxia does not result from failure of spiral arterial modification in mice
E Leno-Durán1, K Hatta, J Bianco
1Department of Anatomy and Cell Biology, Queen's University, Kingston, Ontario, Canada.
Objectives:
To determine if fetal-placental hypoxia is a primary outcome of defective spiral artery remodeling.
Study Design:
Pregnancies in Rag2(-/-)Il2rg(-/-) double knock-out mice, which fail to undergo normal physiological spiral arterial remodeling, were compared to syngeneic BALB/c control pregnancies. Mice at gestation day (gd)6, 8, 10, 12 and 18 were infused with Hypoxyprobe-1 before euthanasia to enable detection of cellular hypoxia by immunohistochemistry.
Results:
In implantation sites of both phenotypes, trophoblast cells were reactive to Hypoxyprobe-1. No major differences were observed between the phenotypes in decidua or placenta at any gd or in gd18 fetal brain, lung, heart, liver or intestine or in maternal heart, brain, liver or spleen. Maternal kidneys from BALB/c were significantly hypoxic to Rag2(-/-)Il2rg(-/-) kidneys.
Conclusions:
In mice, lack of pregnancy-associated spiral artery remodeling does not impair oxygen delivery to the conceptus, challenging the concept that deficient spiral arterial remodeling leads to fetal hypoxia in human gestational complications such as preeclampsia and fetal growth restriction. The isolated hypoxic response of normal kidney has revealed that renal lymphocytes may have unique, tissue-specific regulatory actions on vasoconstriction that are pregnancy independent.

