The effect of neonatal maternal separation on short-chain fatty acids and airway inflammation in adult asthma mice.

BACKGROUND: To investigate neonatal maternal separation (NMS) effects on airway inflammation of asthma and potential mechanism using a mouse model.

METHODS: 80 Balb/c neonatal male mice were randomly assigned to NMS and non-NMS groups. Feces were collected on PND21, 28, 35 and 42 to analyze microbiota and short-chain fatty acids (SCFAs). Non-NMS group were then divided into control (group A) and asthma groups (group B), while NMS group was assigned to NMS+asthma (group C) and NMS+SCFAs+asthma groups (group D). Inflammatory cells and eosinophils (EOS) in bronchoalveolar lavage fluid (BALF) were assessed. Pathological changes and cytokines in lung tissue were observed. Protein expression of Occludin and E-cadherin in airway epithelial was examined.

RESULTS: The number of S', diversity index H' and dominance index D', as well as content butyric acid in NMS group C were significantly lower than non-NMS group B (p<0.05). Mice in group C had a higher level of inflammatory cells and EOS compared with group A, B and D. EOS moderate infiltration was found in mice of group B, C and D. Mice in group C had significantly higher levels of cytokines and showed slightly increased bronchial epithelium goblet cells and a small amount of visceral secretions. Occludin and E-cadherin expression in lung in B, C and D groups was depressed, and protein level in group C was significantly lower than group B and D.

CONCLUSIONS: NMS is associated with exacerbated inflammation of adult asthma by changing intestinal microflora resulting in butanoic acid decline and airway epithelial barrier damage.