Local injection of bone-marrow derived mesenchymal stromal cells alters a molecular expression profile of a contact frostbite injury wound and improves healing in a rat model

Frostbite is a traumatic injury of the tissues upon low temperature environment exposure, which is characterized by direct cell injury due to freezing-thawing followed by development of an acute inflammatory process. Severe frostbite can lead to necrosis of soft tissues and loss of a limb. Mesenchymal stromal cells (MSCs) have a unique ability to modulate pathogenic immune response by secretion of paracrine factors, which suppress inflammation and mediate more efficient tissue regeneration. It should be noted that potential of stem cell therapy for frostbite injury treatment has not been investigated so far. Here, we evaluated a healing capacity of bone-marrow derived MSCs for the treatment of contact frostbite injury wound in a rat model. Cold-contact injury in a Wistar rat model was induced by 1-minute tight application of the cooled probe (−196 ⁰C) to the skin surface of the left hip. Rat bone marrow MSCs were phenotypically characterized and used for local injections into non-damaged tissues surrounding the wound of animals from the experimental group. The second group of rats was treated in the same manner with 1 mL of isotonic sodium chloride solution. Analysis of cytokine and growth factor expression profile in сold-contact injury wounds was performed on days 5, 9, and 16 using immunoblotting and enzyme-linked immunosorbent assay. Animal recovery in MSC-treated and vehicle-treated groups was evaluated by several criteria including body weight recording, determination of eschar desquamation and re-epithelialization terms, assessment of wound closure kinetics, and histological scoring of the wounds on day 23. It turned out that a single subcutaneous administration of MSCs around the wound site resulted in elevated expression of pro-survival and pro-angiogenic VEGF-A and PDGF and 3–5-fold decrease in pro-inflammatory IL-1β as compared with the frostbite wound treated with a vehicle. Moreover, treatment with MSCs caused accelerated wound re-epithelialization (p < 0.05) as well as a better histological score of the MSC-treated wounds. Thus, our data suggested that the use of MSCs is a promising therapeutic strategy for the treatment of cold-induced injury wounds.