Dietary milk fat globule membrane reduces the incidence of aberrant crypt foci in Fischer-344 rats and provides protection against gastrointestinal stress in mice treated with lipopolysaccharide.

摘要

Milk fat globule membrane surrounds the fat droplets of milk. It is a biopolymer containing primarily membrane glycoproteins and polar lipids which contribute to its properties as a possible neutraceutical. The aims of the studies were to determine if dietary milk fat globule membrane: (1) confers protection against colon carcinogenesis; and (2) promotes gut mucosal integrity while decreasing inflammation compared to diets containing corn oil or anhydrous milk fat.;Aim 1. Three dietary treatments differing only in the fat source were formulated: (1) AIN-76A, corn oil; (2) AIN-76A, anhydrous milk fat; and (3) AIN-76A, 50% milk fat globule membrane, 50% anhydrous milk fat. Each diet was formulated to contain 50 g/kg diet of fat and to be identical in macro and micro nutrient content. To assess protection against colon carcinogenesis, male, weanling Fischer-344 rats were randomly assigned to one of the three dietary treatments. Animals were injected with 1,2-dimethylhydrazine once per week at weeks 3 and 4. After 13 weeks animals were sacrificed, colons were removed, and aberrant crypt foci were counted by microscopy.;Rats fed the milk fat globule membrane diet (n = 16) had significantly fewer aberrant crypt foci (20.9 +/- 5.7) compared to rats fed corn oil (n = 17) or anhydrous milk fat (n = 16) diets (31.3 +/- 9.5 and 29.8 +/- 11.4 respectively; P 0.05).;Aim 2. Male BALB/c mice were randomly assigned to one of two diets: AIN-76A, corn oil or AIN-76A, 50% milk fat globule membrane, 50% anhydrous milk fat. After 5 weeks mice were injected with saline vehicle control or lipopolysaccharide and gavaged with dextran-FITC. To assess gut mucosal integrity and inflammation, serum samples were assayed for dextran-FITC 24 and 48 hours after gavage, and a panel of 16 cytokine concentrations was analyzed.;Serum concentrations of IL-6, IL-10, IL-17, MCP-1, IFNgamma, and TNFalpha decreased and gut permeability decreased 45% in lipopolysaccharide challenged mice fed milk fat globule membrane diet compared to control diet at 24 hours (P 0.05).;Overall, the results of these aims suggest that diets containing milk fat globule membrane are protective against colon carcinogenesis, inhibit the inflammatory response, and protect against gastrointestinal stress.