Effects of intra-amniotic meconium exposure on the fetal rat: development of a pathogenic model.
OBJECTIVE
To develop an in vivo animal model for the study of the effects of intrauterine meconium exposure on the fetus.


METHODS
Timed pregnant Long-Evans rats were purchased on gestational day (GD) 12 and allowed to acclimate for at least 48 h prior to surgery. Laparotomy was performed and both uterine horns were exteriorized through the abdominal incision. A 26-gauge needle was used to inject either 0.1-cm(3) sterile normal saline or a 20% meconium suspension into each individual gestational sac. The uterus was returned to the abdomen and the incision was closed. On GD 21 (term = 21 days) a cesarean section was completed and the number and viability of fetuses in each horn were recorded.


RESULTS
A total of 14 animals were involved in this pilot study. One rat underwent sham surgery with only intra-amniotic saline injection and 13/15 fetuses survived to term. Two animals that underwent surgery on day 18 expired < 24 h postinjection. Eleven maternal animals were injected on GD 20 and underwent cesarean delivery at term; survival rates for saline-injected animals were 71.2% compared to 66.2% for meconium-exposed fetuses.


CONCLUSIONS
We have established an in vivo animal model that allows for the examination of the effects of prolonged intrauterine meconium exposure on the fetus.
Blackwell
S C
SC
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Wayne State University/Hutzel Hospital, Detroit, Mich., USA. mfmboy@aol.com
Hallak
M
M
Hotra
J W
JW
Hassan
S S
SS
Berry
S M
SM
Sorokin
Y
Y
D000653:Amniotic Fluid; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008470:Meconium; D008471:Meconium Aspiration Syndrome / Q000503:physiopathology*; D011247:Pregnancy; D051381:Rats; D020318:Rats, Long-Evans; D014599:Uterus / Q000601:surgery