Ultrasound-based monitoring of early mesenchymal stem cell therapy mitigates severe radiation-induced soft tissue injury in minipigs.

PURPOSE: Cutaneous radiation syndrome (CRS) arises from high dose-ionizing radiation exposure and remains a major clinical challenge owing to limited effective therapies. This study investigated the time-dependent therapeutic potential of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) for treating radiation-induced soft tissue injury in a Göttingen minipig model.

MATERIALS AND

METHODS

Six minipigs were locally irradiated with 100 Gy gamma radiation on each thigh. Two animals served as irradiated group (IR group), whereas four received local intradermal hUCB-MSC injections five times, initiated at week 1 (early treatment; Group I) or week 7 (delayed treatment; Group II) post-irradiation. Serial ultrasonographic and color Doppler imaging were used to monitor changes in skin thickness, vascularity, and edema. Gross morphological and histopathological evaluations were conducted to assess wound progression and tissue repair.

RESULTS

All irradiated minipigs developed severe radiation-induced skin burns. Ultrasonography detected skin thickening and vascular abnormalities at early time points, prior to the appearance of gross morphological changes, suggesting that vascular damage precedes visible lesions. Compared with IR group, both MSC-treated groups exhibited reduced ulcer formation, edema, and skin thickness, as confirmed by ultrasound and gross inspection. Early hUCB-MSC administration (Group I) markedly improved wound healing, reduced scab formation, and preserved tissue structure, whereas delayed treatment (Group II) showed limited recovery with persistent necrosis and thick scabbing.

CONCLUSIONS

Early administration of hUCB-MSCs combined with noninvasive ultrasonographic diagnosis effectively mitigates radiation-induced skin injury and promotes wound repair. Ultrasound-based monitoring combined with time-dependent MSC therapy may represent a promising strategy for the clinical management of severe CRS.