title: Coxsackievirus B3 induces apoptosis in the early phase of murine myocarditis: a comparative analysis of cardiovirulent and noncardiovirulent strains.
abstract: OBJECTIVE
  To investigate the relationship between enteroviral infection and myocardial tissue apoptosis during the development of viral myocarditis in a murine model.
  
  
  METHODS
  C3H/HeJ mice were inoculated with two strains of coxsackievirus B3, specifically CVB3 (cardiovirulent Nancy strain) and CVB3/0 (noncardiovirulent strain). Mice were sacrificed at 4, 7 and 10 days postinfection (p.i.). Hearts were removed, and plaque assays and RT-PCR were performed to detect the presence of viruses. Myocardial tissue sections were additionally evaluated by hematoxylin and eosin staining for inflammation, VP1 and Bax immunohistochemical staining for detection of virus and Bax expression, and TUNEL and Apostain for localization of apoptosis.
  
  
  RESULTS
  CVB3 replicated to significantly higher titers than CVB3/0 at all time points. Histopathological analyses revealed significant inflammatory changes at all time points in CVB3-infected mice, in contrast to minimal changes in CVB3/0-infected mice. TUNEL and Apostain assays of myocardial tissues from mice infected with CVB3 disclosed maximum apoptotic lesions at 4 days p.i. and to a lesser extent at 7 and 10 days p.i. Moreover, CVB3-infected myocardial tissues displayed significantly enhanced Bax expression at 4 days p.i., and lesions overlapped with VP1-stained areas.
  
  
  CONCLUSIONS
  These data indicate that (1) the cardiovirulent strain CVB3 induces more severe inflammation and apoptosis than the noncardiovirulent CVB3/0 strain, (2) viral replication is localized in inflammatory and apoptotic lesions in myocardial tissues, (3) apoptotic changes are observed in the early stages of myocarditis and (4) Bax may be associated with the apoptosis process in CVB3-induced myocarditis.
authors.affiliation: Department of Microbiology, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Chul Hyun
authors.initials: CH
authors.lastname: Joo
authors.forename: Hea Nam
authors.initials: HN
authors.lastname: Hong
authors.forename: Eun Ok
authors.initials: EO
authors.lastname: Kim
authors.forename: Jin Ok
authors.initials: JO
authors.lastname: Im
authors.forename: Seung-Yong
authors.initials: SY
authors.lastname: Yoon
authors.forename: Jeong Sook
authors.initials: JS
authors.lastname: Ye
authors.forename: Mi Sun
authors.initials: MS
authors.lastname: Moon
authors.forename: Donghou
authors.initials: D
authors.lastname: Kim
authors.forename: Heuiran
authors.initials: H
authors.lastname: Lee
authors.forename: Yoo Kyum
authors.initials: YK
authors.lastname: Kim
mesh_terms: D000818:Animals; D017209:Apoptosis; D004195:Disease Models, Animal; D029822:Enterovirus B, Human / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004769:Enterovirus Infections / Q000473:pathology / Q000821:virology; D006801:Humans; D051379:Mice; D008809:Mice, Inbred C3H; D009205:Myocarditis / Q000473:pathology* / Q000821:virology; D009206:Myocardium / Q000473:pathology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D010948:Viral Plaque Assay; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; C494827:Bax protein, mouse; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein