03064naa a2200157 a 450000100080000000500110000800800410001910000110006024501070007126000090017852025200018765300200270765300170272765300110274477301510275510812142011-10-11       2011    bl uuuu     u00u1 u    #d1 aEpagri  aCryopreservation of somatic cells in 0.5 ML or 0.25 ML straws and propylene glycol or ethylene glycol.  c2011  aThe standard protocol for the cryopreservation of somatic cells makes use of cryovials as classic containers for the storage of cells, and dimethyl sulfoxide (DMSO) as the cryoprotectant agent of choice. However, cryovials take significant space into LN2 tanks , and DMSO can be highly toxic and induce differentiation in cells in culture. Thus, the aim of this study was to establish a protocol for cryopreservation of somatic cells in straws comparing the efficiency of three cryoprotectant agents: DMSO, Ethylene Glycol (EG) and Propylene Glycol (PG). Primary cell cultures of bovine fibroblasts were maintained in DMEM + 10% FCS in an incubator at 5% CO2 in air and saturated humidity. Such cells were used for nine experimental groups varying the cryoprotectant agent (DMSO, EG, PG) and the container (0.25 and 0.5 mL straws and cryovials). Cells were frozen in a solution containing 10% of one of the cryoprotectants in culture medium. For this, cells were loaded into the container and exposed to the cryoprotectant at 4?? C for 15 min before freezing. Straws were kept in LN2 vapor for 5 min and then immersed in LN2, whereas cryovials were cooled at -1??C/min down to -80??C, using Mr. Frosty??(Nalgene), and then transferred to LN2. The experiment was separated in two steps for the survival study, evaluated by the Trypan blue staining. In the first step, the survival rate was evaluated immediately after thawing (seven replications). In the second step, cell survival was evaluated after 24 h of culture (only for the groups usning straws, in nine replications). Results were evaluated by the ??2, for p&lt0.05. The rate of cell survival immediately after thawing showed no significant differences between the cryoprotectants and containers, with survival rates for DMSO, EG and PG being 83%, 86% and 87% in 0.5 mL straws ; 81%, 83% and 87% in 0,25 mL straws; and 87%, 90% and 91% in cryovials, respectively. Survival rates after 24 h of culture also showed no significant difference between cryoprotectants (DMSO, EG or PG), with survival rates being 91%, 90% and 91% for 0.5 mL straws, and 91%, 91% and 93% for 0.25 mL straws, respectively. In summary, the freezing of somatic cells in straws was proven practical and feasible, facilitating storage of larger batches of cells in LN2 tanks , also providing the same cell viability after freezingas cryovials. Moreover, EG and PG can be readily used as cryoprotectant agents for somatic cell freezing with the same cell survival efficiency as for DMSO.  aCryoprotectants  aSomatic cell  aStraws  tIn: REUNI??O ANUAL DA SOCIEDADE BRASILEIRA DE TECNOLOGIA DE EMBRI??ES, 25., 2011, Cumbuco, CE. [Abstracts]. Porto Alegre, RS: UFRGS, 2011. p. 454.