ABSTRACT
BACKGROUND: Adipose-derived mesenchymal stem cells (ADSCs) that are manufactured in good manufacturing practice (GMP) clean rooms should be made into stem cell preparations before administration. Low-temperature preparation has many advantages over cryopreservation preparation; however, little is reported on the effect of short-term low-temperature storage on the biological characteristics of stem cells. OBJECTIVE: To evaluate the effect of 24-hour low-temperature storage using multiple electrolytes containing 5% human serum albumin on the biological characteristics of ADSCs.METHODS: ADSCs at passages 3-6 at a concentration of 5×109/L were suspended in multiple electrolytes containing 5% human serum albumin. Cell suspension was transferred into cryogenic vials, and then these vials were placed in a cold chain shipping box for 2-8 ℃ low-temperature storage for 24 hours. Cell morphology, adhesion ability, cell viability, cell diameters and cell immunophenotyping before and after the storage were observed. RESULTS AND CONCLUSION: (1) After low-temperature storage of ADSCs for 24 hours, the number of dead cells increased. Although cell viability decreased significantly, it was still higher than 80%. Cell diameters of living cells increased significantly. (2) After low-temperature storage of ADSCs for 24 hours, few cells which were circle-shaped lost adhesion ability, and most cells could adherently grow, with the spindle-shaped morphology similar to the cells before preservation. (3) After low-temperature storage of ADSCs for 24 hours, HLA-DR, CD34 and CD45 were negatively expressed with a positive rate lower than 2%; CD29, CD73 and CD105 were positively expressed with a positive rate higher than 95%. However, the cell cluster was clearly divided into two parts after the preservation. Cells with enlarged diameters moved right in the FSC/SSC dot-plot. These results show that low-temperature preparation storage has no significant effect on the stemness of ADSCs, such as adhesion ability, cell viability and cell immunophenotype.