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Effects of bacterial colonization on mucosal structure of the large bowel of neonatal rats
1Department of Anatomy, University of the Witwatersrand, Johannesburg, South Africa.
Insights
Bacterial colonization in infant rats causes micro-anatomical changes in the colon and caecum, leading to epithelial lesions. Preventing colonization with antibiotics preserves normal mucosal morphology, suggesting bacterial impact on gut development.
Area of Science:
- Gastroenterology
- Developmental Biology
- Microbiology
Background:
- Postnatal development of the gastrointestinal tract involves complex interactions between host and microbiota.
- The large bowel mucosa undergoes significant changes from birth to weaning.
Purpose of the Study:
- To investigate the micro-anatomical changes in the colonic and caecal epithelia of infant rats.
- To determine the role of bacterial colonization in these developmental changes.
Main Methods:
- Comparison of conventional (microbiota-colonized) and antibiotic-treated (microbiota-depleted) infant rats.
- Histological examination of colonic and caecal tissues at different ages (10-22 days).
Main Results:
- Conventional infant rats (15-22 days) exhibited subepithelial spaces, epithelial rupture, and enterocyte plaque loss in the colon and caecum.
- Antibiotic-treated rats maintained the mucosal morphology of 10-day-old rats, lacking these lesions.
- The observed mucosal lesions resembled ischaemic damage, potentially linked to lumen anoxia during bacterial colonization.
Conclusions:
- Bacterial colonization significantly influences the micro-anatomical development of the infant rat large bowel.
- The observed lesions are likely a consequence of the host's response to microbial colonization, possibly involving anoxic events.
- Understanding these interactions is crucial for comprehending gut development and potential pathologies.
Abstract:
Micro-anatomical changes in colonic and caecal epithelia of infant rats between birth and weaning appear to be the outcome of the effects of bacterial colonization, superimposed on the natural postnatal ontogeny of the mucous membranes. Conventional rat pups between 15 and 22 days of age showed development of subepithelial spaces in both caecum and colon, rupture of the overlying epithelium and loss of whole enterocyte plaques. Antibiotic-treated animals retained the large-bowel mucosal morphology of the 10-day-old rat, without any of the lesions described in conventional infants. Mucosal lesions were typical of ischaemic damage, possibly triggered by lumen anoxia during colonization.