title: Escherichia coli induces apoptosis and proliferation of mammary cells.
abstract: Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection. The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection. Induction of matrix metalloproteinase-9, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue. These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation.
authors.affiliation: Department of Animal Science, McGill University, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Long
authors.forename: A V
authors.initials: AV
authors.lastname: Capuco
authors.forename: D L
authors.initials: DL
authors.lastname: Wood
authors.forename: T
authors.initials: T
authors.lastname: Sonstegard
authors.forename: G
authors.initials: G
authors.lastname: Tomita
authors.forename: M J
authors.initials: MJ
authors.lastname: Paape
authors.forename: X
authors.initials: X
authors.lastname: Zhao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D020170:Caspase 1 / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D002455:Cell Division / Q000235:genetics / Q000276:immunology*; D004926:Escherichia coli / Q000378:metabolism / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000473:pathology / Q000503:physiopathology*; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000382:microbiology* / Q000473:pathology / Q000503:physiopathology; D008414:Mastitis, Bovine / Q000382:microbiology* / Q000473:pathology / Q000503:physiopathology; D019278:Matrix Metalloproteinase 3 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
chemical_list: D019394:Ki-67 Antigen; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D014568:Urokinase-Type Plasminogen Activator; D020170:Caspase 1; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9