Lactobacillus paracasei FZJJH2L6 alleviates cathartic Colon via the propionic Acid-5-HT-ACh pathway

Cathartic colon (CC), a form of constipation induced by the chronic abuse and dependence on stimulant laxatives. The application of probiotics to alleviate related diseases has become the research hotspot. In this study, a CC model was constructed by intragastric administration of senna extract, and Lactobacillus paracasei CCFM1164 was used as a positive control to screen strains that can alleviate this constipation. The findings indicate that Lactobacillus paracasei FZJJH2L6 effectively mitigates cathartic colon. The potential mechanisms were explored from the perspectives of enteric nerve repair and intestinal barrier restoration. Results demonstrated that Lactobacillus paracasei FZJJH2L6 increased the content of propionic acid in feces by increasing the relative abundance of short-chain fatty acids-producing bacteria. This upregulated acetylcholine and 5-hydroxytryptamine levels in the colon, reduced intestinal inflammation, repaired the intestinal mechanical barrier, and ultimately alleviated CC. This study provides a theoretical basis for the use of probiotics in alleviating cathartic colon. • Lactobacillus paracasei FZJJH2L6 effectively alleviated cathartic colon. • Lactobacillus paracasei FZJJH2L6 can reduce intestinal inflammation, repair intestinal barrier, and increase 5-HT and ACh content. • Lactobacillus paracasei FZJJH2L6 improved the concentration of propionic acid in feces.