Disialyllacto-N-tetraose improves intestinal homeostasis of metabolic microenvironment to prevent the pathological development of necrotizing enterocolitis in neonatal rats / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the effects of disialyllacto-N-tetraose (DSLNT) on low molecular weight metabolic profile of intestinal contents in neonatal rats with necrotizing enterocolitis (NEC), in an attempt to explore the protective mechanism of DLSNT on intestinal tract of neonates.Methods:Immediately after birth, SD rats were randomly divided into the control group, the NEC group and the NEC+ DSLNT group according to random number tale method.All rats were hand-fed by special formula milk.Rats in the NEC group and NEC+ DSLNT group were exposed to hypoxia (950 mL/L nitrogen, 10 min, thrice per day) and cold stress (4 ℃, 10 min, thrice per day) for continuous 3 days to establish rodent NEC model.Rats in the NEC+ DSLNT group were hand-fed with special formula containing 300 μmol/L DSLNT.All rats were sacrificed after 72 h, and intestinal contents were collected from ileum and colon, followed by untargeted metabolomic determination with the ultrahigh-performance liquid chromatography Q extractive mass spectrometry (UHPLC-QE-MS) method.The terminal ileum was examined by hematoxylin-eosin staining.The metabolome data were analyzed with multivariable analysis using SIMCA 14.1.The metabolites that met both variable importance in the projection (VIP) >1 in the orthogonal partial least squares analysis (OPLS-DA) model and P<0.05 in the t-test were screened as differential metabolites between groups. Results:DSLNT reduced the incidence of NEC and pathological scores of ileum tissue from neonatal rats with NEC [3.0(2.0, 3.0) scores vs.1.0(1.0, 2.0) scores, P<0.01], and also significantly suppressed inflammatory infiltration.OPLS-DA model based on the metabolome data determined by UHPLC-QE-MS could perform effective discrimination between the NEC group and the control group, as well as the NEC+ DSLNT group and the NEC group.There were 64 differential metabolites between the NEC group and the control group (VIP value>1 and P<0.05 for the OPLS-DA model). These metabolites included docosahexaenoic acid (+ 288.0%, P=0.028), xanthine (+ 372.1%, P=0.007), L-arginine (+ 233.1%, P=0.027), L-leucine (+ 232.7%, P=0.015), N-acetylneuraminic acid (-41.6%, P=0.014), and so forth.These metabolites were associated with 34 metabolic pathways.Among them, such 6 pathways as arginine biosynthesis, arginine and proline metabolism were the most disturbed pathways affected by NEC.There were 15 diffe-rential metabolites in between NEC+ DSLNT group and NEC group, which included D-mannose (-73.5%, P=0.032), xanthine (-63.4%, P=0.008), linoleic acid (+ 137.9%, P=0.047), nicotinamide adenine dinucleotide (+ 278.2%, P=0.005), and so forth.These metabolites were mapped to 7 metabolic pathways, among them, linoleic acid metabolism pathway was the most relevant differential pathway affected by DSLNT.There were 8 overlapped meta-bolites in both comparison strategies, and the variation trend of these overlapped metabolites in the NEC group was significantly reversed by DSLNT supplementation. Conclusions:DSLNT could significantly attenuate the NEC pathological damage caused by hypoxia/cold stress in neonatal rats.This protective effect is associated with the improvement of the metabolic profile of intestinal contents caused by NEC and the modulation of the linoleic acid metabolic pathway.The early preventive supplementation of DSLNT is of great significance in maintaining neonatal intestinal homeostasis and preventing the process of NEC.