Bifidobacterium longum subsp. infantis CCFM1269 alleviates neonatal maternal separation-induced colic in rats by regulating serotonin metabolism, NGF/TrkA signaling pathway and gut microbiota

Abstract

Infantile colic (IC), a common functional gastrointestinal disorder in early life, affects approximately 20% of infants worldwide and is associated with long-term health risks; nevertheless, effective interventions remain limited. This study investigated the alleviating effects and underlying mechanisms of Bifidobacterium longum subsp. infantis CCFM1269 on neonatal maternal separation (NMS)-induced IC-like symptoms in rats. The results showed that CCFM1269 intervention significantly increased the visceral pain threshold, decreased colonic 5-HT levels and the number of enterochromaffin (EC) cells, downregulated mRNA expression of the NGF/TrkA signaling pathway, and reduced hippocampal corticotropin-releasing factor (CRF). In addition, CCFM1269 modulated gut microbiota composition, enriched beneficial bacterial populations, elevated propionate and butyrate, and alleviated neuroinflammatory responses in both serum and the hippocampus. In conclusion, B. longum subsp. infantis CCFM1269 alleviates NMS-induced IC-like symptoms by regulating the NGF/TrkA signaling pathway, reducing EC cell counts and 5-HT production, and modulating the gut microbiota and short-chain fatty acid metabolism, providing new evidence for probiotic intervention in infantile colic.