Non-Adherent Bone Marrow-Derived Mesenchymal Stem Cells Ameliorate Clinical Manifestations and Inflammation in an Experimental Model of Ulcerative Colitis in Rats

BACKGROUND: Functional and developmental versatility of mesenchymal stem cells (MSCs) have generated great interest in their clinical application. Recently, it has been proposed that the non-adherent population of bone marrow cells can differentiate to MSCs in vitro. The present study aimed to compare the anti-inflammatory potentials of adherent and non-adherent MSCs in an experimental model of ulcerative colitis (UC) in rats. METHODS: The present experimental study was conducted at the School of Veterinary Medicine, Urmia University (Urmia, Iran) during March-May 2018. UC was induced using acetic acid in three groups of male Wistar rats, namely the control colitis, adherent MSCs treated, and non-adherent MSCs treated groups. Adherent and non-adherent MSCs were collected, characterized, and proliferated. The isolated cells were injected into the peritoneum of the respective groups of colitis rats. After 10 days, the animals were evaluated for gross and microscopic pathology, production of inflammatory mediators, and stress oxidative profile in the gut tissue. The statistical analysis was performed using SPSS software (version 23.0). P<0.05 was considered statistically significant. RESULTS: The non-adherent MSCs had almost similar therapeutic potency compared to the adherent MSCs (P=0.12). They significantly reduced the level of inflammatory mediators and improved the oxidative stress profile in colonic tissue compared to the control colitis group (P=0.0001). CONCLUSION: The molecular assays and histopathological assessment revealed that the non-adherent MSCs not only had anti-inflammatory and regulatory potency but also enhanced tissue regeneration in UC rats. Therefore, the non-adherent fraction of bone marrow-derived MSCs could be used as a complementary source of MSCs in stem cell therapies.