Dead but functional liquid nitrogen-treated umbilical cord mesenchymal stem cells accelerate full-thickness skin wound healing

Abstract

Background: The direct application of umbilical cord-derived mesenchymal stem cells (UCMSCs) for promoting skin wound healing and regeneration is challenging due to strict maintenance requirements and unpredictable differentiation results. Methods: We developed dead but functional liquid nitrogen-treated UCMSCs (LNT-MSCs) by rapidly immersing live UCMSCs (live-MSCs) in liquid nitrogen. Results: The LNT-MSCs maintained similar cellular structures and surface markers to those of live-MSCs. We evaluated the therapeutic effects of both live-MSCs and LNT-MSCs on full-thickness skin wound healing in rats. Our results showed that the LNT-MSCs accelerated wound closure by enhancing the proliferation and migration of skin cells, promoting angiogenesis, and inducing a favourable macrophage phenotype shift. The regenerative healing effect of LNT-MSCs was comparable to that of live-MSCs, making them a potential alternative strategy for accelerating wound closure that avoids unpredictable differentiation results and creates a ready-to-use cell bank for clinical applications.