Histocompatibility and Cryopreservation Laboratory, Department of Histology and Embryology, Institute of Biology Roberto Alcantara Gomes, Rio de Janeiro State University, 20950-003 Rio de Janeiro, Brazil.
Cryobiology. 2010 Jun;60(3):301-7. doi: 10.1016/j.cryobiol.2010.02.002. Epub 2010 Feb 10.
Transplantation using hematopoietic stem cells from umbilical cord blood (UCB) is a life-saving treatment option for patients with select oncologic diseases, immunologic diseases, bone marrow failure, and others. Often this transplant modality requires cryopreservation and storage of hematopoietic stem cells (HSC), which need to remain cryopreserved in UCB banks for possible future use. The most widely used cryoprotectant is dimethylsulfoxide (Me(2)SO), but at 37 degrees C, it is toxic to cells and for patients, infusion of cryopreserved HSC with Me(2)SO has been associated with side effects. Freezing of cells leads to chemical change of cellular components, which results in physical disruption. Reactive oxygen species (ROS) generation also has been implicated as cause of damage to cells during freezing. We assessed the ability of two bioantioxidants and two disaccharides, to enhance the cryopreservation of UCB. UCB was processed and subjected to cryopreservation in solutions containing different concentrations of Me(2)SO, bioantioxidants and disaccharides. Samples were thawed, and then analysed by: flow cytometry analysis, CFU assay and MTT viability assay. In this study, our analyses showed that antioxidants, principally catalase, performed greater preservation of: CD34+ cells, CD123+ cells, colony-forming units and cell viability, all post-thawed, compared with the standard solution of cryopreservation. Our present studies show that the addition of catalase improved the cryopreservation outcome. Catalase may act on reducing levels of ROS, further indicating that accumulation of free radicals indeed leads to death in cryopreserved hematopoietic cells.
脐带血（UCB）来源的造血干细胞移植是某些肿瘤疾病、免疫疾病、骨髓衰竭和其他疾病患者的救命治疗选择。通常，这种移植方式需要对造血干细胞（HSC）进行冷冻保存和存储，这些细胞需要在 UCB 库中冷冻保存，以备将来可能使用。最广泛使用的冷冻保护剂是二甲基亚砜（Me2SO），但在 37°C 下，它对细胞有毒，对于患者来说，输注含有 Me2SO 的冷冻保存 HSC 与副作用有关。细胞冷冻会导致细胞成分的化学变化，从而导致物理破坏。活性氧（ROS）的产生也被认为是细胞在冷冻过程中受损的原因。我们评估了两种生物抗氧化剂和两种二糖增强 UCB 冷冻保存的能力。对 UCB 进行处理并在含有不同浓度 Me2SO、生物抗氧化剂和二糖的溶液中进行冷冻保存。解冻样品后，通过流式细胞术分析、CFU 测定和 MTT 活力测定进行分析。在这项研究中，我们的分析表明，抗氧化剂，主要是过氧化氢酶，在所有解冻后的 CD34+细胞、CD123+细胞、集落形成单位和细胞活力方面都比标准冷冻保存溶液更好地保存。我们目前的研究表明，添加过氧化氢酶可以改善冷冻保存效果。过氧化氢酶可能作用于降低 ROS 水平，进一步表明自由基的积累确实导致冷冻保存的造血细胞死亡。
