Morphological Adaptation of the Cardiovascular System in Fetal Rats
during Late Gestation
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MANATOMO TOYONO, TADAHIKO
ITO, KENJI HARADA,
MASAMICHI TAMURA and GORO
TAKADA
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Department of Pediatrics, Akita University School of Medicine, Akita
010-0041
The aim of this study was to evaluate morphological changes of the
cardiovascular system in fetal rats during late gestation. We used the
rapid whole-body freezing technique for rats of day 17 through 21 of
gestation. The right and left ventricular volumes increased markedly and
significantly during this period by about 11- and 24-fold, respectively.
Although the right ventricular volume was 108% larger with statistical
significance than the left ventricular volume on day 17, they were
almost equal after day 19. The length of the primum septum of the atrium
significantly increased by 92% within 4 days, but the opening distance
of foramen ovale significantly decreased by 14%. The ratio of the inner
diameter (the sum of right and left pulmonary arteries to ductus
arteriosus) significantly increased from 0.72±0.03 on day 17 to
1.17±0.07 on day 21. There was also a significant increase in the
ratio of the inner diameters of the ascending to descending aorta. These
observations suggest that the reduction of the opening distance of
foramen ovale reflect the growth of pulmonary arteries.
Key words---
whole-body rapid freezing technique; fetal rats; cardiovascular system;
morphological changes.
© 1999 Tohoku University Medical Press
Tohoku J. Exp. Med., 1999, 188, 299-309
Address for reprints: Manatomo Toyono, M.D., Department of Pediatrics,
Akita University School of Medicine, 1-1-1 Hondo, Akita 010-0041, Japan.
e-mail: toyono@rd5.so-net.ne.jp
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