Effects of galacto-oligosaccharide ingestion on the mucosa-associated mucins and sucrase activity in the small intestine of mice.
BACKGROUND
Galacto-oligosaccharides (GOS) are non-digestible oligosaccharides with short galactosyl chain units produced by lactose fermentation which are considered as prebiotics. Only few studies have investigated the effects of GOS medium-term ingestion on the small intestinal epithelium characteristics.


OBJECTIVE
In this study, we evaluated the consequences of GOS ingestion on small intestinal mucosal morphology, on brush-border membrane enzyme activities and on mucin content in BALB/c mice.


METHODS
Mice received the experimental diets for 4 weeks and then the small intestine was collected to measure sucrase, lactase and alkaline phosphatase activities, to study the villus heights in the jejunum mucosa and to determine mucosal mucin content as well as MUC-2 and MUC-4 mRNAs expression by qRT-PCR.


RESULTS
Our results showed that GOS has no detectable effect on the intestine villus height but increased the total protein content by twofold. Sucrase activity was significantly increased in the intestinal mucosa recovered from animals fed the GOS diet without any detectable modification of lactase and phosphatase activities. Interestingly, GOS was also able to increase sucrase activity in cultured Caco-2 cells raising the view that they likely act directly on these cells. Furthermore, GOS was found to markedly increase O-linked glycoproteins associated with the intestinal mucosa without modifying MUC-2, MUC-4 mRNAs expression. Lastly, TNF-alpha mRNA expression was also not modified after GOS ingestion.


CONCLUSIONS
These results suggest that, in BALB/c mice, 4-week GOS ingestion is able to increase the small intestinal mucosa-associated mucin content and enterocyte-associated sucrase activity without modifying villus height.
Leforestier
Géraldine
G
INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, 16 rue Claude Bernard, 75005, Paris, France.
Blais
Anne
A
Blachier
François
F
Marsset-Baglieri
Agnès
A
Davila-Gay
Anne-Marie
AM
Perrin
Emmanuel
E
Tomé
Daniel
D
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D018938:Caco-2 Cells; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology* / Q000473:pathology*; D007421:Intestine, Small / Q000201:enzymology / Q000473:pathology; D043322:Lactase / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008871:Microvilli / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D009077:Mucins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D009844:Oligosaccharides / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013393:Sucrase / Q000187:drug effects / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D009077:Mucins; D009844:Oligosaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000469:Alkaline Phosphatase; D043322:Lactase; D013393:Sucrase