Intestinal mucin distribution in the germ-free rat and in the heteroxenic rat harbouring a human bacterial flora: effect of inulin in the diet

Abstract

A colorimetric method was used on water-soluble much extracted from m u d scraping!? and contents of the caecum and the colon of five germ-free (GF) rats and five heteroxenic (HE) rats harbouring a hnmao flora (GF rats d a t e d with a human flora). These rats were fed on a diet containing either 100 g sucrose/kg or 100 g inulin/kg. Histological stains, periodic aciMChiff, alcian blue pH 2.5 and alcian blue pH0-5 were used to discriminate between neutral, acidic and acidic sulphated mucins respectively. Spectrocolorimetric assays led to a calculated absorbance value for 1 mg of the initial much extract. Each much type was compared between treatments. The caecal contents of GF rats contained more acidic mucin than sulphomucin, which was present in the same proportion as neutral mucin. Their colonic contents contained more acidic mucins than sulphomucin, which in turn was more abundant than neutral mucin. Their caecal mucosa mucin distribution differed from that of the contents: very little acidic much was present and neutral and dphomucin proportions were of the same order of magnitude. Inulin increased the amount of neutral much in the caecal contents and of sulphated mucios in the colonic contents and increased the amounts of neutral and acidic mucins in the caecal mucwa. Mucin distribution in the HE rats was very different from that in the GF rats: the caecal contents contained a high proportion of acidic m u c h and very little sulphomucin. The same distribution of mucins was observed in the colonic contents. The caecal mucaw contained less acidic much and more sulphomucin than the caecal contents. Inulin decreased acidic mucins and increased sulphated m u c h in the caecal contents and increased neutral and sulphated mucins in the colonic contents. Inulin increased sulphomucin in the caecal m u m and decreased acidic much in the caecal and colonic mucosas. The very low amount of mucin that was recovered in the colonic mucosa suggests that, in the presence of the bacterial flora and associated with inulin in the diet, much was extensively released from the mucosa to the colonic lumen. This might be related to the bacterial metabolites produced.

The distribution of mucous secreting cells in the gastrointestinal tracts of three small rodents from Saudi Arabia: Acomys dimidiatus , Meriones rex and Meriones libycus

“…Similarly, an increase in numbers of mucus secreting goblet cells is present in the colon of the human (Forstner, 1978) and three insectivorous mammalian species (Boonzaier et al, 2013). Due to the vulnerability of sialomucins to bacterial degradation, sulfomucin secreting cells are expected to dominate in the large intestine where the bacterial load is high (Fontaine et al, 1996, Deplancke and Gaskins, 2001, Hino et al, 2012and Machado-Neto et al, 2013. This was true in M. rex in the present study where the number of sulfomucin secreting goblet cells increased significantly towards the distal GIT.…”

“…Contrary to these findings, sulfomucins were more common than sialomucins in the caeca of both Meriones species studied here, although mixed acid mucins predominated in the caeca of these species. The high viscosity and acidity of acid mucus enables resistance against the attack of bacterial enzymes (Fontaine et al, 1996 andDeplancke andGaskins, 2001). This is important in the caecum as it is regarded as a site for bacterial fermentation in herbivores (Forstner, 1978).…”

Análise morfométrica da parede intestinal e dinâmica de mucinas secretadas no jejuno de frangos suplementados com probiótico Bacillus subtilis cepa C3102

“…O principal componente da camada de muco são as mucinas glicoprotéicas (Smirnov et al 2006), as quais podem ser ácidas ou neutras (Uni et al 2003). A mucina ácida funciona como barreira bacteriana (Fontaine et al 1996, Roberton & Wright 1997 ou sítio de ligação a microbiota intestinal.…”

Selective in vitro degradation of the sialylated fraction of germ-free rat mucins by the caecal flora of the rat

“…Les [8,17,[25][26][27]. Changes in the proportions of mucin types are also reported under certain pathological conditions [6,15,[19][20][21][22].…”

“…The complexity of this degradation has been recently reviewed [13]. We [17] and also mucin-type distribution both in the mucosa and intestinal contents, as compared to GF rats [8]. An [14].…”