Disease-modifying efficacy of alginate-microencapsulated probiotics in an animal model of ulcerative colitis

Ulcerative colitis (UC) can be challenging to control with current therapies. Modulating gut dysbiosis with probiotics is a promising approach, but the benefits depend on keeping the cell viability as they pass through gastrointestinal transit (GIT). This study developed an alginate microencapsulation system and evaluated its overall disease-modifying efficacy in an acetic acid-induced colitis model. Lactiplantibacillus plantarum and Levilactobacillus brevis were microencapsulated in calcium alginate beads via extrusion. Encapsulation efficiency, morphology, and viability under simulated GIT conditions were assessed. Forty-two male Wistar rats (non-colitic control; acetic acid-induced colitis) were gavaged for up to 12 days with normal saline, free or encapsulated probiotics, and/or mesalazine. Disease Activity Index (DAI), colon weight/length, histopathology, and colonic IFN-γ expression were measured; statistical significance was P < 0.05. Results displayed that encapsulation yielded a high efficiency (91.00% ± 1.69%). In simulated GIT conditions, Δ0-120 log CFU was significantly smaller for encapsulated than for free probiotics. Combination of encapsulated probiotics with mesalazine (EMT) showed the lowest weight loss score across all probiotic-based groups (p < 0.05). DAI declined from day 2 onward in most groups; by day 5, animals given encapsulated probiotics remained significantly different from non-colitic controls (p < 0.05). Histopathological assessment showed that either encapsulated or free probiotics significantly lower histopathological scores compared to the colitis group (p < 0.001), and real-time PCR revealed a significant difference between the EMT group compared to the colitis group (p < 0.05). Together, alginate-microencapsulated formulations were more effective than free probiotics with regard to outcome improvements, indicating a viable UC management strategy that needs further investigation.