Background: Multipotent mesenchymal stem cells (MSCs) have been used in inflammatory bowel diseases because of their immunomodulatory and regenerative properties. We investigated their local use in an experimental model of colitis in the rat.
Materials and methods: Colitis was induced into 20 Wistar rats with local TNBS instillation. Allogeneic stem cells were derived from rat adipose tissue and labeled with PKH2 linker dye with creation of a control and a second group treated by a local injection into the rectal wall of 2×10⁶ allogeneic adipose tissue-derived stem cells (ADSCs). The thicknesses of different components of the rectum were measured with comparisons made in different parts of the colon of the Hunter inflammatory score. PKH2-dyed ADSCs were detected by fluorescence microscopy.
Results and conclusions: Total colitis was induced in 19/20 rats with homing of fluorescent ADSCs. to the crypt base and perivascular space of the submucosa. There were no differences in component rectal wall thicknesses with a higher Hunter score in the treated group compared with the controls, in the rectum (3.8±2.74 vs. 1.5±2.37, respectively; p=0.017) and in right colon (2.5±1.08 vs. 0.20±0.42, respectively; p=0.0001). Local colonic injection of allogeneic adipose stem cells. in experimental colitis is feasible and safe. There is demonstrable homing of cells in chemically-induced colitis both to the treated region and parts of the colon distant to the MSC treatment site. Such cells readily proliferate in vitro and could potentially be a source for future treatment of resistant disease.
Keywords: Animal models; Colitis; Inflammatory bowel disease; Mesenchymal stem cells.