High-fat-diet alters the oligosaccharide chains of colon mucins in mice

Mucins are high molecular weight epithelial proteins, highly glycosylated, and are the main component of the mucus. In human, colon mucus, which is acidic, both sulfate and carboxylate, mainly consists of MUCIN2 (MUC2). Since mucus secretion can be altered in disease, colon mucins can be regarded as a biomarker of chronic inflammatory bowel diseases or pre-neoplastic changes. Aims. We aimed to assess mucus alterations occurring during a high-fat diet . Methods. Conventional histochemistry and lectin histochemistry were employed to analyze the carbohydrate features of colon mucins in 12 adult mice divided in control group (standard rodent diet) and group on high-fat diet (HFD) for 25 weeks. Results. In the distal colon, HFD mice showed a significant increase of the ratio sialo/ sulfomucins ratio compared with control mice (47.27 ±9.8% vs. 21±4.8%, respectively). After desulfation both in proximal and distal colon, lectin binding patterns in the whole glandular crypts were increased in HFD mice compared with controls (score 3 vs. 2, respectively). Conclusions. A Western-style high-fat diet in animal models promotes an increased ratio sialo/sulfomucins, altered lectin binding pattern of the mucus, and a likely shortening of oligosaccharide chains of glycoproteins. Such alterations resemble those occurring in humans in chronic inflammatory bowel or in pre-neoplastic diseases. As a high-fat diet might be associated with colon cancer, analysis of lectins histochemistry might detect abnormal expression of mucin patterns in early neoplastic changes of the colon.