Efficacy of Composite Microecologics in the Treatment of Crohn's Disease and Its Effects on the Gut Microbiota

Objective  To explore the efficacy of composite Microecologics on colitis in rat with Crohn's disease (CD) induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) and their impact on the intestinal flora.

Methods  SD rats were divided into four groups: Control, TNBS, Model (TNBS + Microecologics), and TNBS + 5-aminosalicylic acid (5-ASA). Each group contained four rats. Key parameters included body mass, disease activity index, colon length, and mucosal damage index scores. Colonic tissue was evaluated using hematoxylin-eosin (HE) staining, Masson staining, PAS glycogen staining, immunohistochemical analysis, Western blot, and ELISA to assess efficacy. Gut microbiota alterations were analyzed using 16s rRNA high-throughput sequencing.

Results  Compared with the TNBS group, the TNBS + Microecologics group showed a significant reduction in DAI scores (P < 0.05), improved colon shortening (from 14.53 cm to 17.67 cm, P < 0.05), lower mucosal damage scores (P < 0.01), and a marked decrease in collagen fiber proportion (from 24.18% to 12.36%, P < 0.01). The expression of the tight junction proteins ZO-1 (P < 0.05) and Claudin-1 (P < 0.01) was upregulated, and the number of goblet cells increased significantly (average count from 63 to 279.3, P < 0.01). Levels of inflammatory cytokines showed statistically significant differences: tumor necrosis factor α (TNF-α) (P = 0.001), interleukin (IL)-1β (P < 0.05), and IL-6 (P < 0.001) decreased, while IL-10 (P < 0.01) increased. Overall, the therapeutic effect of the microecological preparation was superior to that of the TNBS + 5-ASA group. Beta diversity of the gut microbiota in the Microecologics group improved significantly (P = 0.001). At the phylum level, compared with the Control group, the TNBS group showed a decreased relative abundance of Firmicutes (P < 0.01) and an increased abundance of Bacteroidetes (P < 0.001). Intervention with the microecological preparation reversed these changes, increasing Firmicutes (P < 0.05) and decreasing Bacteroidetes (P < 0.05) abundance compared with the TNBS group. The relative abundance of Chloroflexota was higher in the Control group than in the Microecologics group (P < 0.05). LEfSe analysis indicated significant enrichment of Lactobacillus following the microecological intervention.

Conclusion  Composite microecological preparations can play a therapeutic and remission-inducing role in Crohn's disease by reducing inflammatory factors, promoting the recovery of intestinal barrier function, and improving the balance of colonic microecology.