Growth retardation and microcephaly induced in mice by placental infection with murine cytomegalovirus.
BACKGROUND
The placenta is regarded as a site of congenital cytomegalovirus (CMV) infection. The placental infection of fetuses with murine CMV (MCMV) was investigated in a mouse model.


METHODS
The placentas and fetuses were examined using the polymerase chain reaction (PCR) and Southern blotting for viral DNA and immunostaining for viral antigen. Since the transplacental infection rarely occurs, the placentas were directly injected with MCMV at day 12.5 of gestation; the embryos were then allowed to develop until day 18.5 of gestation.


RESULTS
Formation of infected foci at day 18. 5 of gestation was found in more than 60% of the injected placentas. Infection of about 50% of the embryos occurred from the infected placentas. The frequency of infection in the brain was 27%, which was the same as that in the liver and higher than that in the lungs. In the brains, infected cells were often observed in the ventricular zone of the cerebrum and sometimes in the cortical plate and the hippocampus. Developmental retardation with microcephaly was observed in about 25% of offspring exposed to infection in utero.


CONCLUSIONS
These results suggest that formation of infected foci in the placenta is important for embryonic congenital infection, and that the cerebral ventricular zone is one of the most susceptible sites for CMV infection in the embryonic stage.
Second Department of Pathology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
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Li
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Tsutsui
D000818:Animals; D000831:Animals, Newborn; D015139:Blotting, Southern; D001835:Body Weight; D001921:Brain / Q000196:embryology / Q000473:pathology / Q000821:virology; D003586:Cytomegalovirus Infections / Q000150:complications*; D005260:Female; D005315:Fetal Diseases / Q000821:virology; D005317:Fetal Growth Retardation / Q000821:virology*; D007150:Immunohistochemistry; D008099:Liver / Q000196:embryology / Q000821:virology; D008168:Lung / Q000196:embryology / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D008831:Microcephaly / Q000196:embryology / Q000821:virology*; D009929:Organ Size; D010922:Placenta Diseases / Q000821:virology*; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D014409:Tumor Necrosis Factor-alpha