The Effects of Mesenchymal Stem Cell Therapy on Colon Anastomosis in Rats Subjected to Radiotherapy

Objective: Colorectal cancer is the third most common malignancy worldwide. Although neoadjuvant radiotherapy (nRT) improves local control in rectal cancer, it increases the risk of anastomotic leakage. Mesenchymal stem cells (MSCs) have been shown to support wound healing. This study aimed to evaluate the effects of MSC therapy on anastomotic healing after nRT in a rat model.Material and Methods: Fifty-five Wistar Albino rats were allocated into four groups: control, nRT, nRT + local MSCs, and nRT + local + intraperitoneal MSCs. A single 12 Gy dose of radiotherapy was administered preoperatively to the nRT groups. Each rat received a total of approximately 1 × 10⁶ adipose-derived MSCs in 0.1 mL; in the local MSC group, the entire dose was administered subserosally to the anastomotic site, whereas in the combined group, half of the dose was administered locally and the remaining half intraperitoneally. Anastomotic healing was assessed using burst pressure (BP), histopathological evaluation, and biochemical analyses.Results: Rats receiving nRT demonstrated significant weight loss and lower BP values. In the MSC-treated groups, BP values were higher compared with the nRT-only group, although these differences did not reach statistical significance. Histopathological and biochemical parameters did not differ significantly among the groups. Notably, gross anastomotic separation was observed only in the nRT-only group, whereas no such separation was detected in the MSC-treated groups. Fluorescent imaging confirmed the presence of differentiated MSCs at the anastomotic site.Conclusion: Although MSC therapy did not result in statistically significant improvements in biochemical or histopathological parameters, the absence of gross anastomotic separation and the tendency toward higher burst pressure values suggest that MSCs may support local anastomotic healing after neoadjuvant radiotherapy. These findings indicate a potential role for MSC therapy as an adjunctive strategy, warranting further experimental and clinical investigation.