Cell culture and variations in the comet assay do not affect the genomic integrity of adipose-derived stem cells

Abstract

The application of quality control tests, such as the comet assay, are essential when adipose-derived stem cells are cultured for therapeutic purposes. However, the steps involved in the development of this assay should be investigated, in order to reduce their influence on genomic damage in cells. The study aimed to evaluate if the cell culture process causes DNA damage, and if variations in the lysis time and pH of the electrophoresis buffer interfere in the genotoxicity results. Four different comet assay protocols were evaluated, and the effects of lysis time and pH conditions of the electrophoresis buffer solution were stated as follows: 2 hours and pH 12; 24 hours and pH 12; 2 hours and pH ≥ 13 and 24 hours and pH ≥ 13. The tail moment was analyzed, and results indicated that at the time cells were detached from the flasks, there was little damage to the DNA in the adipose-derived stem cells, which was confirmed by evaluation of the expression of mRNA genes involved in damage and repair processes of genetic material. Also, the tail moment values ​​did not show significant differences among the four evaluated protocols (p < 0.05), with no indication of damage when compared to the positive control (p < 0.05). Thus, any of the tested protocols can be applied in genotoxicity tests with adipose-derived stem cells, without causing damage to them.