Effects of Bacterial Colonization on Mucosal Structure of the Large Bowel of Neonatal Rats

Hill, R.R.H.; Cowley, H. M.

doi:10.1159/000146578

Cited by 5 publications

(5 citation statements)

References 5 publications

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“…The antibodies used in our study are directed against the common framework of the MHC complex in the rat and less specific than the murine antibodies used by Matsumoto et al [26], We have studied the cecum and other areas of the colon and site differences have appeared with epithelial cells of the cecum showing positive staining after conventionali zation while the remaining colon was nega tive. In addition, other authors have also shown that bacterial colonization has an im portant influence of the large bowel mucosa in rats and like us described initial epithelial damage in the cecum [27].…”

Section: Discussionsupporting

confidence: 61%

Anthranoids and the Mucosal Immune System of the Colon

et al. 1993

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The mechanism of action of anthranoids in general and of sennosides at the cellular level is not precisely known. Pseudomelanosis or pseudolipofuscinosis, a condition characterized by the accumulation of pigmented macrophages in the lamina propria, is one of the well-known effects of these products. It is most probably the result of an interaction between apoptotic epithelial cells and the lamina propria cellular infiltrate. Treatment of cell suspensions of intestinal epithelial cells and of human intestinal epithelial cells in culture with rhein anthrone, the active compound of sennosides, demonstrates a direct influence of the drug on these epithelial cells. Low doses induce alterations in cellular shape and organelles consistent with increased metabolism. High doses induce apoptotic changes. The interaction between the epithelial cells and cells of the monocyte/macrophage lineage induces also the release of prostaglandins of the E series as shown by experiments on cell cultures of epithelial cells and peripheral blood cells. An increase of PGE2 release to about 140% of the control value is noted following administration of low doses of rhein anthrone to a combination of human intestinal epithelial cells and human peripheral blood mononuclear cells. This finding indicates that rhein anthrone is activating cellular components of the intestinal immune system and may by this pathway induce secretion and motility.

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Section: Discussionsupporting

confidence: 61%

Anthranoids and the Mucosal Immune System of the Colon

et al. 1993

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“…Goblet cells are decreased in specific pathogen free mice in comparison with germ-free ones. Therefore, the formation of intestinal microflora leads to a decrease in the mucin secretion [20]. Thus, the difference in regulation of indigenous bacteria between the basal portions of the mucosal folds in the proximal colon and the middle colon might be caused by other defense factors such as the regulation of the host's mucin secretion, in addition to the regulation of epithelial kinetics.…”

Section: Discussionmentioning

confidence: 99%

Histoplanimetrical Study on the Relationship between Cellular Kinetics of Epithelial Cells and Proliferation of Indigenous Bacteria in the Rat Colon

Yamamoto

Yokoo

et al. 2009

The Journal of Veterinary Medical Science

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ABSTRACT. The aim of this study was to clarify the regulatory effects of epithelial kinetics on indigenous bacterial proliferation in the large intestine. The lifespan, migration speed and proliferation rate of crypt epithelial cells in the initial 20% of the colon (proximal colon) and the 50% of the colon (middle colon) in bromodeoxyuridine-administrated rats were histoplanimetrically and chronologically compared. The proximal colon possessed well-developed mucosal folds and a large amount of indigenous bacteria which filled the crypt lumen, whereas no folds or bacteria were found to occupy the crypt lumen in the middle colon. The cell lifespans were 32.2, 42.5 and 33.6 hr in the apical and the basal parts of the mucosal folds of the proximal colon, and in the middle colon, respectively. The migration speeds were 4.2, 2.1 and 3.3 m/hr, respectively, while the appearance frequencies of proliferating cell nuclear antigen (PCNA)-positive crypt epithelial cells were 35.0, 24.6 and 33.8%. These findings suggest that the lifespan was shortened and the migration speed increased in the most luminal mucosa of colon, contributing to the elimination of the adhered bacteria from the most luminal mucosa. By contrast, the elongation of the lifespan and deceleration of the migration of epithelial cells in the basal parts of the mucosal folds might contribute to reliable settlement of indigenous bacteria, resulting in the maintenance of a large amount of indigenous bacteria in the lumen of the proximal colon.

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“…However, we think that the difference in the period after colonization may be responsible for the difference in expression of IFN-related genes between our study and theirs. The inflammation induced by microbial colonization of GF animals has been known to be only temporary and cease within several weeks [ 62 , 63 ]. After the inflammation is terminated, histological findings return to a state apparently indistinguishable from the normal intestines of mice genuinely harboring the microbes.…”

Section: Discussionmentioning

confidence: 99%

Importance of the interferon-α system in murine large intestine indicated by microarray analysis of commensal bacteria-induced immunological changes

et al. 2008

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BackgroundAlthough microbiota play a critical role in the normal development and function of host immune systems, the underlying mechanisms, especially those involved in the large intestine (LI), remain unknown. In the present study, we performed transcriptome analysis of the LI of germ-free (GF) and specific pathogen-free (SPF) mice of the IQI strain, an inbred strain established from ICR mice.ResultsGeneChip analysis, quantitative real-time RT-PCR, and reconfirmation using bacteria-inoculated GF mice revealed differences in the expression levels of several immune-related genes, such as cryptdin-related sequences (CRS), certain subsets of type 1 interferon (IFN)-related genes, class Ib MHC molecules, and certain complements. LI expressed no authentic cryptdins but predominantly expressed CRS2, 4, and 7. The mRNA levels of IFN-related genes, including Irf7, Isgf3g, Ifit1 and Stat1, were lower in SPF- and flora-reconstituted mice. When an oral IFN-α inducer tilorone analog, R11567DA, was administered to SPF mice, IFN-α was induced rapidly in the LI at 4 h, whereas no IFN-α protein was detected in the small intestine (SI) or blood. In situ hybridization and immunohistochemistry suggested that the IFN-α production originated from Paneth cells in the SI, and portions of lamina proprial CD11b- or mPDCA1-positive cells in the LI.ConclusionThe present study suggests that microbial colonization, while inducing the expression of anti-microbial peptides, results in the down-regulation of certain genes responsible for immune responses, especially for type I IFN synthesis. This may reflect the adaptation process of the immune system in the LI to prevent excessive inflammation with respect to continuous microbial exposure. Further, the repertoire of anti-microbial peptides and the extraordinary role of interferon producing cells in the LI have been found to be distinct from those in the SI.

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Effects of Bacterial Colonization on Mucosal Structure of the Large Bowel of Neonatal Rats

Cited by 5 publications

References 5 publications

Anthranoids and the Mucosal Immune System of the Colon

Anthranoids and the Mucosal Immune System of the Colon

Histoplanimetrical Study on the Relationship between Cellular Kinetics of Epithelial Cells and Proliferation of Indigenous Bacteria in the Rat Colon

Importance of the interferon-α system in murine large intestine indicated by microarray analysis of commensal bacteria-induced immunological changes

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