Effects of Intra-Amniotic Meconium Exposure on the Fetal Rat: Development of a Pathogenic Model

• Published in: Fetal diagnosis and therapy Vol. 16; no. 4; pp. 203 - 207
• Main Authors: Blackwell, Sean C., Hallak, Mordechai, Hotra, John W., Hassan, Sonia S., Berry, Stanley M., Sorokin, Yoram
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland Karger 01.07.2001; S. Karger AG
• Subjects: Amniotic Fluid; Animals; Biological and medical sciences; Disease Models, Animal; Diseases of mother, fetus and pregnancy; Female; Gynecology. Andrology. Obstetrics; Humans; Infant, Newborn; Meconium; Meconium Aspiration Syndrome - physiopathology; Medical sciences; Pregnancy; Pregnancy. Fetus. Placenta; Rats; Rats, Long-Evans; Uterus - surgery; Meconium; Meconium-stained amniotic fluid; Fetal rat; Animal model; Pregnancy disorders; Rat; Rodentia; Vertebrata; Fetal diseases; Mammalia; Animal; Amniotic fluid; Complication; Fetus; Technique
• ISSN: 1015-3837; 1421-9964
• DOI: 10.1159/000053910

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. Conclusion: We have established an in vivo animal model that allows for the examination of the effects of prolonged intrauterine meconium exposure on the fetus.