Murine trophoblast failure and spontaneous abortion

Area of Science:

• Reproductive biology
• Developmental toxicology
• Immunology

Background:

• Spontaneous abortion is a complex issue, with infection proposed as a potential initiator.
• The specific role of viral infections in spontaneous pregnancy loss in mice remains largely untested.

Purpose of the Study:

• To investigate the effects of the antiviral drug ribavirin on pregnancy outcomes in mice.
• To explore the potential mechanisms by which ribavirin may induce abortion, focusing on embryo development and trophoblast function.

Main Methods:

• Female mice (CBA/J and C3H/HeJ) were administered ribavirin orally starting the day after mating with DBA/2J males.
• Embryo development, trophoblast hypoplasia, and associated immune cell infiltration were assessed.
• In vitro studies evaluated ribavirin's effect on trophoblast and mastocytoma cell proliferation.

Main Results:

• Ribavirin treatment significantly increased abortion rates (resorption) by day 13.5 of gestation.
• This increase was linked to retarded embryo development and trophoblast hypoplasia.
• A reduction in trophoblast-associated suppressor activity was observed, with no maternal mononuclear cell infiltrate, potentially due to ribavirin's immunosuppressive effects. Ribavirin suppressed trophoblast and mastocytoma cell proliferation in vitro.

Conclusions:

• Ribavirin induces abortion in mice through a mechanism primarily involving direct impairment of trophoblast development.
• This study provides a drug-induced murine abortion model for investigating spontaneous pregnancy failure.
• The findings highlight the importance of considering direct drug toxicity on placental development in pregnancy loss research.