Observations of proliferation and division of frozen-thawed mesenchymal stem cells (MSCs) using a time-lapse cinemicroscopy.

Cryopreservation and culture of human cells and tissues are indispensable techniques not only for the regenerative medicine but also for the conservation of gene resources. The cinemicroscope recording of the cell-lysis during freezing and thawing process and of the cell proliferation in the culture dishes in 5 % CO2 at 37 °C has played an important role superior to still images. We have previously elucidated the mechanisms of cryo-destruction and -protection of the human blood and tissue cells using cryomicroscopic observation, which were recorded by a high-speed 16 mm movie camera since 1967 (Sumida, 1973; 1974; 2016). Recently, we made the time-lapse cinemicroscope recording of proliferation, differentiation, and division of mesenchymal stromal cells (MSC) derived from frozen-thawed adult human adipose tissue in a specially designed small incubator sized of 25×85×125 mm (BlAST Inc. Japan) for cell and tissue culture which was incorporated on the stage of inverted microscope Nikon DIAPHOT-TMD, using NIKON D800 camera. These results will help to elucidate the mysterious behaviour of MSCs, which have solved some problems in clinical use of human MSCs, artificially induced on plastic surfaces, in regenerative medicine (Sumida, 2016).