Abdominal Distension and Escherichia coli Peritonitis in Mice Lacking Myeloid Differentiation Factor 88.
Here we describe the gross and microscopic findings of naturally occurring, β-hemolytic Escherichia coli peritonitis in B6.129-Myd88(tm1Aki) male and female mice. Over approximately 5 mo, 10 homozygous mutant mice deficient in myeloid differentiation factor 88 (C57BL/6 strain; male and female) that had not been used in research protocols developed rapid-onset abdominal swelling associated with copious viscous ascites. Each mouse developed an anterior peritonitis, primarily involving the parietal peritoneum and the visceral surface of the spleen, liver, diaphragm, and stomach. Inflammation was confined to the organ surfaces, with no indication of septicemia or grossly apparent gastrointestinal perforation or other tissue compromise that would initiate peritonitis. Peritonitis was likely attributable to compromised antibacterial innate immunity; cohoused, similarly immunodeficient littermates did not develop similar clinical signs. An unusual finding in all cases was mesothelial cell hyperplasia and hypertrophy. Although the underlying innate immune deficiency accounts for much of the observed pathology, the remarkable mesothelial cell morphology and the episodic nature of the peritonitis in some littermates and not others remain unexplained.
College of Public Health, Medical and Veterinary Science, James Cook University, Townsville, Queensland, Australia. linda.johnson2@jcu.edu.au.
Linda K
LK
Johnson
College of Public Health, Medical and Veterinary Science, James Cook University, Townsville, Queensland, Australia; Faculty of Veterinary Medicine, Nusa Cendana University, Kupang, East Nusa Tenggara, Indonesia.
Antin Yn
AY
Widi
Comparative Genomics Centre, James Cook University, Townsville, Queensland, Australia.
Serrin
S
Rowarth
Comparative Genomics Centre, James Cook University, Townsville, Queensland, Australia.
Alan G
AG
Baxter
D000005:Abdomen / Q000473:pathology; D000818:Animals; D001201:Ascites / Q000209:etiology / Q000276:immunology / Q000473:pathology; D004195:Disease Models, Animal; D004927:Escherichia coli Infections / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D005260:Female; D007153:Immunologic Deficiency Syndromes / Q000209:etiology / Q000276:immunology / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000172:deficiency* / Q000235:genetics / Q000276:immunology; D010538:Peritonitis / Q000209:etiology* / Q000276:immunology / Q000473:pathology
C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88