Therapeutic Efficacy of Subcutaneous and Intraperitoneal Injections of a Single Dose of Human Umbilical Mesenchymal Stem Cells in Acute and Chronic Colitis in a Mouse Model

Purpose: Intraperitoneal (IP) injection of mesenchymal stem cells (MSCs) has been reported to treat colitis in mice. Complications such as abdominal organ injury and infection are significant concerns. We studied a single injection of human umbilical cord MSCs (hUCMSCs) via the subcutaneous (SC) and IP routes in mice with colitis. Methods: Male C57BL/6Ncrl mice were divided into control, phosphate-buffered saline (PBS), hUCMSCs SC, and hUCMSCs IP injection groups. Colitis was induced by 3% dextran sulfate sodium (DSS). The disease activity index (DAI), colon length, histology, inflammation score, cytokine and chemokine staining and in vivo stem cell images were recorded. Results: The DAI in the SC group was significantly lower than that in the IP group during late acute colitis. The colon was significantly shorter, and the colon inflammation score was significantly higher in the PBS group than the control group. There were no significant differences in the colon length and inflammation score between the control group and the SC and IP groups. The expressions of IL17A and Gro-α decreased in the SC group compared with those in the IP group on the 8th and 25th days. hUCMSCs via SC injection accumulated in the subcutaneous tissue to the 25th day. Conclusion: hUCMSCs via SC and IP injection reduced DSS-induced acute colitis and decreased progression to chronic colitis. The anti-inflammatory effects of hUCMSCs were better in the SC injection group than the IP injection group. In clinical practice in humans, SC injection of hUCMSCs is relatively safer and more convenient than IP injection.