Efficacy of umbilical cord-derived mesenchymal stem cells and exosomes in conjunction with standard IBD drug on immune responses in an IBD mouse model.

Background: Inflammatory bowel disease (IBD) is a persistent inflammation of the digestive system, and Mesenchymal Stem Cells (MSCs) and their exosomes have demonstrated potential as treatments for this condition. The objective of this research was to examine the possible effectiveness of intraperitoneal injection of umbilical cord-MSCs (UC-MSCs) and their exosomes through a two-time injection regimen in a mouse model.

Method: In this study, an animal model of a specific type of IBD in C57BL/6 mice, induced by dextran sulfate sodium (DSS), was utilized. The mice were treated with MSCs, exosomes, Mesalazine, and a combination of them. Upon sacrificing the mice, colon and spleen tissues were isolated to assess the changes in the mice's weight, colon length, spleen weight, and colitis' pathological symptoms. IL-10 and IL-17 levels were measured, and Treg and Th17 cell percentages were determined as well. Furthermore, colon tissue was stained to investigate histopathological changes.

Results: In the groups that received MSCs, there was a significant reduction in the disease activity index and their combinations with exosomes and Mesalazine compared to the colitis group. Colon length increased in all groups except the exosome group. Histological measures were notably reduced in the MSC groups and their combinations. Significant increases in the IL-10 level of colon tissue and the proportion of Treg present in the spleen were observed in the groups receiving MSC and combination treatment. Furthermore, these groups showed a notable reduction in the percentage of spleen Th17 cells. However, IL17A decreased non-significantly in all groups.

Conclusion: The results showed that intraperitoneal injection of UC-MSCs and their combination with exosome and Mesalazine in a murine colitis model improved the disease's symptoms. Therefore, MSCs and their combination with exosomes can be a promising therapeutic approach along with other common drugs for IBD, but exosomes alone could not significantly reduce the symptoms of colitis.