DEVELOPMENT OF
A MOUSE MODEL CYTOMEGALOVIRUS INFECTION FOR HUMAN CONGENITAL CENTRAL
NERVOUS SYSTEM
Tang J-L1,
Wang M-L2, Qiu J-J1, Hu W3, Shi B-F2, Hu Y2, Li J-P2, Bi K-J2
1Department of
Pediatrics, the First Affliated Hospital of Anhui Medical University,
Hefei, China
2Department of
Microbiology, Anhui Medical University, Hefei, China
3Department of
Pathology, the Second Affliated Hospital of Anhui Medical University,
Hefei, China
Objective: The aim of this work was to define that Human
Cytomegalovirus (HCMY-AD169) can cross the placenta of the BALB/C mice and
initiate congenital infection of the developing fetus.
Methods: HCMV-AD169 (5.0 log TCID50 in 0.5 ml/mouse) was
injected into the intraperitoneum of mice (half of mice are female) when
they were about 8~12 weeks old. Then, these of mice were arranged for
mating .Pregnancies were dated as day 0 when a copulation plug was found
.Fetuses on the day about to give birth of gestation were removed from the
uteri and the its cerebral cortex was remove from the skull and fixed with
4% paraformaldehyde ,then cut into sections 5 um thick, applided to slides
coated with Histostik , and then stained with hematoxylin and eosin (H.E.)
.And observed and photographed with the microscopy and the electronic
microscopy . Meanwhile, the supernatant of mince of fetus mouse brain
tissue was used for virus isolates by HF cells. And viral DNA-positive
cells were examined by in situ hybridization using digoxigenin labelled
HCMV DNA oligonucleotide probe in the acetone fixed imprint of the cerebral
cortex.
Results:
The results observed showed that
pathological changes consisting of destructive meningoencephalitis and
large, basophilic, intranucleus and acidophilous intracytoplasmic neuronal
inclusions of viral type occurred in the fetus mouse brain. With the
electronic microscopy we found that the nerves cells body expanded, nuclear
located inclined, stained deeply, mitochondrion became contract and even
dispersion, Golgi complex and Endoplasmec Reticulum became dispersion and
dissolution,the virus particles was found in the nucleus and acytoplasmic ,
and the cells in the vessels is about to apoptosis. Meanwhile the presence of virus
sequences was confirmed by in situ hybridization, however, nothing was
found in the normal controls; HCMV had also been isolated from the tissue
supernatant. The positive rate of serum specific IgM and IgG of the female
mice in HCMV infection group was 73.9% and 95.7% respectively, and that of
normal control group was 4.2% and 12.5% respectively by ELISA. The results
showed there are significant difference between two groups (P<0.01). And
the stillbirth rate and the mortality rate within the first week at birth
of the offspring which were beared by its mothers injected with HCMV were
much evidently higher than those of the normal control (P<0.01).
Conclusion: Our research suggested that the central nervous
system (CNS) of a fetus mouse become infected as a result of transplacental
transmission of HCMV during symptomatic maternal infection. The mouse model
will allow the study of the pathogenesis of HCMV congenital CNS infection
and the development of therapeutic agents and vaccines.