An animal model of intrauterine growth retardation induced by synthetic thromboxane a(2).
OBJECTIVE
Intrauterine growth retardation (IUGR) is an important cause of prenatal and neonatal morbidity, and neurologic abnormalities. Although several animal models of IUGR have been developed for scientific investigation, few models approximate the pathophysiology in human fetal growth failure resulting from pregnancy-induced hypertension and preeclampsia. We developed an animal model of IUGR in which fetal growth restriction was induced by administering a synthetic thromboxane A(2) analogue (STA(2)) to the mother.


METHODS
Timed pregnant Sprague-Dawley rats were used in this study. STA(2) was delivered into the peritoneal cavity of the pregnant female at a rate of 20 ng/h from day 13 of pregnancy. The effectiveness of this model was evaluated by monitoring the overall growth of the fetuses and neonates and measuring the weight and biochemical composition of individual organs.


RESULTS
Fetuses and neonates from the STA(2) group showed a highly significant weight reduction throughout the observation period from day 19 of gestation to postnatal day 7. Weight reduction near and at term exceeded 10% and became more pronounced during the first week after birth. Fetuses on the 20th gestational day exhibited a pattern of growth retardation characteristic of asymmetrical IUGR in which the weight reduction was prominent in the liver with relative sparing of the brain. However, the decrease in brain weight was more than 10%. The protein, DNA, and RNA contents of the liver were lower in the STA(2) group. The protein content of the forebrain and brainstem also decreased significantly in the STA(2) group compared with the control; however, the DNA content of the forebrain was higher in the STA(2) group.


CONCLUSIONS
This animal model may mimic human IUGR more closely than previous models because the growth restriction is induced in a truly chronic manner.
Hayakawa
Masahiro
M
Maternity and Perinatal Care Center, Nagoya University Hospital, Nagoya, Japan. masahaya@med.nagoya-u.ac.jp <masahaya@med.nagoya-u.ac.jp>
Takemoto
Koji
K
Nakayama
Atsushi
A
Saito
Akiko
A
Sato
Yoshiaki
Y
Hasegawa
Masayuki
M
Ieda
Kuniko
K
Mimura
Shunji
S
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D005317:Fetal Growth Retardation / Q000139:chemically induced*; D007263:Infusions, Parenteral; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013928:Thromboxane A2 / Q000008:administration & dosage* / Q000031:analogs & derivatives*
D013928:Thromboxane A2; C037866:STA 2