ИСТИНА

Usually human embryonic stem cells are expanded as adherent flat colonies on feeder cells. These colonies can be composed of several cell layers. The cells of the lower layer attached to the substrate and characterized by well-defined stress fibers, whereas cytoskeleton of other cells in colony had a cortical localization. It has been shown that incubation of cells at 370C for 10 min in 10 % DMSO induces the cytoskeleton rearrangements – disassembling of stress fibers that led to detaching HESCs from the substrate and their dissociation. These rearrangements were reversible – stress fibers appeared again after incubation of cells for 20 min, in culture medium without DMSO. It should be noted that fibroblasts, which were used as a feeder, did not exhibit such quick disassembling of cytoskeleton structures after described DMSO treatment and remain attached to the culture surface. The quantity of damaged cells after such treatment was much lower than after enzymatic dissociation. The ability of hESCs to dissociate after short-term incubation in culture medium with 10 % DMSO permit to obtain suspension of hESCs which is ready for cryopreservation and also reduce the time and number of steps in the preparation of cells for it.