Effect of a cryopreservation protocol on the proliferation of stem cells from human exfoliated deciduous teeth.

The aim of the present study was to evaluate the influence of a cryopreservation protocol on the proliferation and viability of stem cells from human exfoliated deciduous teeth (SHEDs).Cells from the pulp of three deciduous teeth were isolated and characterized to confirm their stem cell nature. In second passage, part of the cells were submitted to normal conditions of cell culture (Control group), while part of the cells were maintained in 10% DMSO diluted in foetal bovine serum and submitted to the following cryopreservation protocol: 2 h at 4 °C, 18 h at -20 °C and then at -80 °C for two intervals (30 days - Cryopreservation I; and 180 days Cryopreservation II). Cell proliferation and cell cycle were evaluated at intervals of 24, 48 and 72 h after plating, and apoptosis-related events were analyzed at 72 h.All groups exhibited an increase in the number of cells, and no significant differences between the cryopreserved and control groups were observed (p > .05). The distribution of cells in the cell cycle phases was consistent with cell proliferation, and the percentage of viable cells was higher than 99% in all groups, indicating that cell viability was not affected by the cryopreservation protocol throughout the experiment.The proposed cryopreservation protocol is adequate for the storage of SHED, permitting their use in future experimental studies.