title: Murine model for congenital CMV infection and hearing impairment.
abstract: BACKGROUND
  Congenital cytomegalovirus (CMV) infection is the leading cause of sensorineural hearing loss (SNHL), and SNHL is the most frequent sequela of congenital CMV infection. But the pathogenic mechanism remains unknown, and there is no ideal CMV intrauterine infection animal model to study the mechanisms by which SNHL develops.
  
  
  METHODS
  We established the congenital murine cytomegalovirus (MCMV) infection model by directly injecting the virus into the placenta on day 12.5 of gestation. Then, we observed the development and the MCMV congenital infection rate of the fetuses on the day they were born. Furthermore, we detected the auditory functions, the conditions of the MCMV infection, and the histological change of the inner ears of 28-day-old and 70-day-old offspring.
  
  
  RESULTS
  Both the fetal loss rate and the teratism rate of offspring whose placentas were inoculated with MCMV increased, and their body length, head circumference, and weight decreased. The hearing level of offspring both decreased at both 28- and 70-days post birth; the 70-day-old mice developed lower hearing levels than did the 28-day old mice. No significant inflammatory changes in the cochleae of the mice were observed. MCMV DNA signals were mainly detected in the spiral ganglion neurons and the endolymph area, but not in the perilymph area. The number of neurons decreased, and their ultrastructures changed. Moreover, with age, the number of neurons dramatically decreased, and the ultrastructural lesions of neurons became much more severe.
  
  
  CONCLUSIONS
  The results suggest that the direct injection of MCMV into the placenta may efficiently cause fetal infection and disturb the intrauterine development of the fetus, and placental inoculation itself has no obvious adverse effects on offspring. The reduction in the number of spiral ganglion neurons and the ultrastructural lesions of the neurons may be the major cause of congenital CMV infection-induced progressive SNHL.
authors.affiliation: Department of Obstetrics and Gynecology, Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
authors.forename: Chen
authors.initials: C
authors.lastname: Juanjuan
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
authors.forename: Chen
authors.initials: C
authors.lastname: Li
authors.forename: Liu
authors.initials: L
authors.lastname: Haizhi
authors.forename: Wang
authors.initials: W
authors.lastname: Ling
authors.forename: Wang
authors.initials: W
authors.lastname: Xinrong
authors.forename: Xiao
authors.initials: X
authors.lastname: Juan
authors.forename: Liu
authors.initials: L
authors.lastname: Tao
authors.forename: Yin
authors.initials: Y
authors.lastname: Zongzhi
authors.forename: Chen
authors.initials: C
authors.lastname: Suhua
mesh_terms: D000818:Animals; D003586:Cytomegalovirus Infections / Q000150:complications* / Q000151:congenital*; D004195:Disease Models, Animal; D005260:Female; D045888:Ganglion Cysts / Q000473:pathology; D034381:Hearing Loss / Q000151:congenital*; D006651:Histocytochemistry; D006801:Humans; D007759:Labyrinth Diseases / Q000473:pathology / Q000821:virology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018146:Muromegalovirus / Q000472:pathogenicity; D010920:Placenta / Q000821:virology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000473:pathology / Q000821:virology; D012376:Rodent Diseases / Q000151:congenital / Q000821:virology