Lactobacillus acidophilus C4 ameliorates constipation in mice.

Functional constipation (FC) is a common gastrointestinal disorder that can seriously affect patients' quality of life. Probiotics have emerged as a promising strategy for preventing and managing gastrointestinal diseases. Previously, we isolated Lactobacillus acidophilus C4 from the feces of a healthy child, and here, we investigated its probiotic efficacy against FC in a mouse model. Prophylactic treatment with L. acidophilus C4 prior to FC onset significantly reduced impairment of defecation function and increased intestinal transit rate. L. acidophilus C4 also increased the expression of tight junction proteins ZO-1 and occludin, suggesting a protective effect on the intestinal barrier. In addition, L. acidophilus C4 was able to modulate the inflammatory response by decreasing the pro-inflammatory factor IL-1β while increasing the anti-inflammatory cytokine IL-10. These results reveal that L. acidophilus C4 can improve constipation through anti-inflammation and restoration of intestinal barrier function, which can be a candidate strain for the development of novel interventions for constipation.IMPORTANCEFunctional constipation (FC) requires novel therapeutic approaches. Probiotics have attracted attention in the prevention and management of gastrointestinal diseases; however, their efficacy and mechanisms of action against FC need to be verified. This study provides experimental evidence for this purpose, supporting its potential as a non-invasive and well-tolerated intervention. The core of this study is Lactobacillus acidophilus C4, which exhibits high compatibility with the human intestinal microenvironment and lays a foundation for clinical research. L. acidophilus C4 can enhance intestinal peristalsis, protect the intestinal barrier (by upregulating tight junction proteins ZO-1 and occludin), and regulate inflammation (by balancing the pro-inflammatory cytokine IL-1β and anti-inflammatory cytokine IL-10). This strain provides a new direction for research on probiotic-based treatment of FC.