| There are two common infant feeding methods,breastfeeding and formula feeding.However,milk-fed infants are at a disadvantage in overall health development,especially in the incidence of inflammatory bowel disease,which is higher than that of breast-fed infants.Most of the commercially available milk powders are based on milk and contain proteins,fats,vitamins,and trace elements.The ingredients are structurally similar to or even higher than breast milk,so it is widely speculated that the cause of the difference in the health of the two milk-fed infants is the presence of oligosaccharides in human milk.Studies targeting human milk oligosaccharides have focused on free oligosaccharides and less on N-glycans.In terms of structure,the most important two-terminal glycosylation modifications of human milk oligosaccharides are fucosylation and sialylation,which can be subdivided into α-1,6,α-1,3,α-1,4,and a-1,2 four bond-linked fucosylation and a-2,3 and a-2,6 two bond-linked sialylation.Human milk free oligosaccharides have good functional activity in terms of probiotics,antibacterial and immunity.For N-glycans,their immune activity has not been verified.This experiment compared the individual differences in four-bond fucosylation and two bond-type sialylation,differences in lactation,and bond type differences.and used the pro-inflammatory cytokine IL-12 as a standard,to test the immune response in Caco2 cells treated with milk N-glycans to compares the immunological activity of human milk and milk N-glycans.The results are as follows:1.The difference in the relative content of three linkage of fucosylated N-glycan ofhuman milk and bovine milk at different lactation stagesIn order to study the functional properties of different linkage of fucosylated N-glycan in the future,three different sources of human and bovine were selected in this chapter to take breast milk at three different lactations,seven days,one month and six months.N-glycan were extracted from each sample and use EoFuc 0918(α-1,6),EoFuc 3066(α-1,3/4),and AcFuc 3141(α-1,2)to release different linkage of fucose from N-glycans.Then calculate the relative content of each linkage of fucosylated N-glycan.And the significance of the results was analyzed using the LSD test.The result showed that,(1)There were significant differences between different individuals in human milk and bovine milk.Among them,the difference between people is greater than the difference between bo vines.(2)There was also a significant difference between human milk and bovine milk during each lactation period.The difference in most of the samples was mainly the lactation period of 7th days,which was significantly different from the lactation period of 1th month and 6th months,There was no significant difference between the milk of 1th month and 6th months.(3)In human milk and bovine milk,the relative contents of three different linkage of fucosylated N-glycan are not absolute,but they have different expression patterns depending on the individual.(4)There was no significant difference in the relative contents of α-1,6 and α-1,3&1,4 linkages between human milk and bovine milk,but the relative content of α-1,2 fucosylated N-glycans in bovine milk.It is generally higher than human milk.2.The difference in the relative content of two linkage of sialylated N-glycan ofhuman milk and bovine milk at different lactation stagesWe use the same N-glycans sample as last charter,and use two different sialidase to release different linkage of sialic acid on N-glycan.the result was analysisi by LSD test.The result shows that,(1)There is a significant difference between human milk and bovine milk.Which is worth noticing that there is no significance between different bovine at the lactation stage of 7 days.(2)There is a significant difference in lactation between human milk and bovine milk.(3)in general,in human milk,the α-2,3 linkage of sialylated N-glycan decrease with lactation change,and the opposite in bovine milk.for α-2,6 linkage of sialylated At-glycan,it reach to highest relative content in the lactation period of 1th Uouth,and the lowest relative content occoured in the lactation period of 6th mouth in human milk.and in bovine milk,its content decreased by lactation stage.(4)In human milk,the dominant sialylated N-glycan in the lactation period of 7th day is α-2,3 linkage of sialylated N-glycan,Which was opposite in bovine milk.There was no significant difference in the relative content of this two linkage of sialylated N-glycan in the lactation period of 1th mouth and 6th mouth2.Effect of milk N-glycan on cellular immunityTo explore the effect of human milk N-glycans on early immunization of infants,an intestinal model was constructed using human colon carcinoma cell Caco2,using 3 nmol/mL,6 nmol/mL,and 12 nmol/mL N-glycan respectively.Cells subjected to starvatioN-induced inflammation were incubated(blank medium in the control group,lactose in 50 mg/L medium,and 1 μg/mL LPS),and each was incubated in an ELISA kit.The expression level of inflammatory cytokines in the cells was determined.The results are as follows:After incubation,the inflammatory cytokines is still in cells,and the effect of N-glycans on IL-12 in each concentration was U-shaped,and the median concentration of 6 nmol/mL had the strongest anti-inflammation effect,and there was a significant difference compared with the blank control.For bovine milk N-glycan,the same concentration of bovine milk N-glycan will lead to cell death. |
PDF Full Text Request