The aim of this R&D was to prove that nuclei of somatic cells can maintain their functionality following lyophilization, which is the total absence of water.
To test this hypothesis, we have lyophilized somatic cells taken from sheep (granulosa cells and lymphocytes) and we have lyophilized them according to the routine procedures. The first results were negative, and resulted in massive DNA damage of the lyophilized/re-hydrated cells.
On the basis of data published by other researchers, we decided to add a reducing sugar, the threalose, to the freezing medium were the cells to be lyophilized were suspended.
Following this modification, we found that the extedbn of DNA damage was remarkably reduced although the cell viability was compromised. Therefore, we evaluated whether the nuclei from lyophilized cells can be “reactivated” after their injection into enucleated sheep oocytes. To our surprise, lyophilized cells kept at room temperature were able to direct the early embryonic development following nuclear transfer into enucleated oocytes.