Cryopreservation of Rat Bone Marrow Derived Mesenchymal Stem Cells by Two Conventional and Open-pulled Straw Vitrification Methods

Objective: Mesenchymal stem cells (MSCs) are obtained from a variety of sources, mainlythe bone marrow. These cells have a great potential for clinical research, however they cannotstay alive for long periods in culture. The aim of this study is to determine whether vitrificationcan be a useful freezing method for the storage of MSCs.Materials and Methods: Mesenchymal stem cells were isolated from rat bone marrow basedon their capacity to adhere to plastic culture surfaces. MSCs were cryopreserved using boththe vitrification method and open-pulled straw (OPS) vitrification and stored in liquid nitrogenwith ethylene glycol ficoll (EFS) as a cryoprotectant for two months. The morphology andviability of thawed MSCs were evaluated by trypan blue staining. Furthermore, pre and postcryopreserved MSCs were induced to osteocyte and adipocyte with corresponding osteogenicand adipogenic medium.Results: After thawing, the viability rates were 81.33% ± 6.83 for the vitrification method and80.83% ± 6.4 for OPS vitrification, while the values in the pre-vitrification control group were88.16% ± 6.3 (Mean ± SD, n = 6). Post-cryopreserved cells from both the vitrification methodand OPS vitrification also had a similar cellular morphology and colony-formation that wasindistinguishable from non-vitrified fresh MSCs. In addition, the resuscitated cells cultured ininduction medium showed osteogenesis. Mineral production and deposition was detectableby alizarine red S staining. Moreover, by applying an adipogenic differentiation condition,both pre and post cryopreserved cells differentiated into adipocyte and lipid vacuole accumulationthat was stained by oil red O.Conclusion: Vitrification is a reliable and effective method for the cryopreservation of MSCs