Human breast milk oligosaccharides attenuate necrotizing enterocolitis in rats by suppressing mast cell accumulation, DPPI activity and TLR4 expression in ileum tissue, and regulating mitochondrial damage of Caco-2 cells

Int Immunopharmacol. 2020 Nov:88:106881. doi: 10.1016/j.intimp.2020.106881. Epub 2020 Aug 11.

Abstract

Necrotizing enterocolitis (NEC), a devastating infant disease characterized by severe intestinal necrosis, its pathogenesis is poorly understood, but appears to be multifactorial and highly associated with immaturity of gastrointestinal tract and immature innate-immune system. Breast-milk is effective strategy to protect infants against NEC. This study is using a NEC rat model to investigate the pathological mechanism of NEC involved intestinal-damages, and the therapeutic mechanism of sialylated human milk oligosaccharides (SHMOs) on NEC rats; also using cell model to investigate the effects of SHMOs on colon-epithelial cells (Caco-2) in-vitro. Extraction and characterization of SHMOs from breast milk, establishment of a NEC rat model, histopathological analysis and mast cell accounting of the terminal ileum were taken; The levels of DPPI, TLR4, IL-6, TNF-α, MMP-2/9 and glutathione were measured using various methods. Caco-2 cells were pre-treated with SHMOs and cultured with LPS, histamine, chymase or DPPI, cell viabilities and mitochondrial membrane potential were examined; flow cytometry was used to detect cell cycle. The accumulation of mast cells was found in the ileum of NEC rats, but prohibited by SHMOs treatment; the increased levels of TLR4, DPPI, IL-6, TNF-α, MMP-2/9 in NEC ileum were suppressed by SHMOs in-vivo. SHMOs prevented Caco-2 cells from LPS, histamine, chymase induced damages by surviving cell viability, regulating G0/G1 and S phase in cell cycles, and increasing mitochondrial membrane potential. These findings provide a new insight into the pharmacological mechanism of SHMOs treatment for NEC and suggest that SHMOs needs well attention for therapeutic aims.

Keywords: DPPI; Human breast milk oligosaccharides; Intestinal Epithelium; Mast cell; Necrotizing enterocolitis; TLR4.

MeSH terms

  • Animals
  • Animals, Newborn
  • Caco-2 Cells
  • Cathepsin C / metabolism*
  • Cell Cycle / drug effects
  • Disease Models, Animal
  • Enterocolitis, Necrotizing / immunology
  • Enterocolitis, Necrotizing / metabolism
  • Enterocolitis, Necrotizing / prevention & control*
  • Glutathione / metabolism
  • Humans
  • Ileum / drug effects
  • Ileum / pathology*
  • Mast Cells / drug effects
  • Mast Cells / metabolism*
  • Matrix Metalloproteinase 2 / metabolism
  • Membrane Potential, Mitochondrial / drug effects
  • Milk, Human / chemistry*
  • Milk, Human / immunology
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • N-Acetylneuraminic Acid / chemistry
  • N-Acetylneuraminic Acid / immunology
  • N-Acetylneuraminic Acid / pharmacology
  • Oligosaccharides / chemistry
  • Oligosaccharides / immunology
  • Oligosaccharides / pharmacology*
  • Rats, Sprague-Dawley
  • Toll-Like Receptor 4 / metabolism*

Substances

  • Oligosaccharides
  • Tlr4 protein, rat
  • Toll-Like Receptor 4
  • Cathepsin C
  • Matrix Metalloproteinase 2
  • Mmp2 protein, rat
  • Glutathione
  • N-Acetylneuraminic Acid