SPIONs-labeled hUCMSCs for in vitro safety analysis and in vivo tracking in scarred monkey uteri.

Cesarean section has been increasingly used, stem cells have a potential to improve the repairing of scarred uteri, but its mechanism is still unclear. Cell labeling and tracking are becoming increasingly important in stem cell research. In this study, we evaluated the safety and efficacy of labeling human Umbilical Cord Mesenchymal Stem Cells (hUCMSCs) with Superparamagnetic Iron Oxide Nanoparticles (SPIONs), both in vitro and in vivo, with a particular focus on their application as Magnetic Resonance Imaging (MRI) contrast agents injected into the uterus. Monkeys were used as animal models because their structure is similar to that of humans. These results demonstrate that hUCMSCs could be effectively labeled with SPIONs without compromising cellular proliferation or differentiation potential. Furthermore, a minimal impact on cell surface marker expression and immunocytochemical staining for vimentin was observed. MR scanning was conducted both in vitro and in vivo, along with pathological staining, to confirm the effective labeling of SPIONs without significant cytotoxicity. This labeling persisted for more than 600 days, enabling non-invasive, dynamic monitoring of the injection site via MRI. The safety and effective labeling of human Umbilical Cord Mesenchymal Stem Cells (hUCMSCs) with Superparamagnetic Iron Oxide Nanoparticles (SPIONs) for MRI contrast enhancement in uterine repair were conducted in this study. Our findings show no adverse effects on cell proliferation or differentiation, with sustained SPION labeling over 600 days. These findings could help improve scarred uterus regeneration, offering a non-invasive tracking method for stem cell therapies in regenerative medicine.