RESUMO
Objective To study the effect of magnetic rewarming on the morphology and biomechanical properties of vitrified umbilical artery. Methods The vitrified umbilical artery was rewarmed by magnetothermal method and traditional water bath. The temperature distribution and stress in the solution system were analyzed, and the rewarming effect was evaluated by tissue staining and mechanical test. Results Compared with water bath rewarming, the temperature gradient and thermal stress generated by magnetic rewarming were smaller, which could effectively reduce the thermal stress damage during the rewarming stage and achieve rapid and uniform rewarming. Magnetic rewarming could effectively avoid umbilical artery fractures and micro-cracks. After rewarming, the extracellular matrix, collagen fibers, elastic fibers and muscle fibers of the umbilical artery were evenly distributed, which preserved the macro and micro structures of the umbilical artery. The umbilical artery showed different degrees of hardening after water bath and magnetic rewarming, but the elastic modulus and limit stress of the latter were not significantly different from those of fresh umbilical artery, and the latter had unidirectional stretching characteristics similar to that of fresh umbilical artery, showing good elasticity and toughness. Conclusions Compared with water bath rewarming, magnetothermal method can effectively reduce the damage of rewarming stage, ensure the macroscopic, microscopic structure integrity of umbilical artery and better biomechanical properties. The research findings provide important references for cryopreservation of large tissues or organs such as umbilical artery.