Transfection of mesenchymal stem cells at physiological oxygen concentrations

Abstract

Aim. Numerous works showed the beneficial effect of oxygen in physiological concentrations on mesenchymal stem cells (MSC) cultures. The aim of the present work was to study the impact of physiological oxygen tensions on non-viral transfection of MSC from human Wharton jelly (WJ-MSC). Methods. WJ-MSC at passage 2 were cultivated for 48 hours in different gas mixtures: nitrogen-based (oxygen – 3 %, CO 2 – 5 %, nitrogen – 92 %) and argon-based (oxygen – 3 %, CO 2 – 5 %, argon – 92 %), while the control group was cultivated under standard conditions of CO 2 -incubator (ambient oxygen concentration, CO 2 – 5 %). After 48 hours of cultivation the cells were transfected with polyplexes pEGFP-C1/PEI/ and pEGFP-C1/TurboFect, containing 3 μg of plasmid DNA. The cultures were in contact with com­ plexes for 1 hour, at standard conditions of CO 2 -incubator. Next, the media were changed, and WJ-MSC were cultivated for 48 hours in described gas mixtures, and CO 2 – incubator. Transfection effectiveness was estimated by flow cytometry as the number of eGFP+ fluores­ cent cells, (BD FACSAria). Results. In the groups cultivated in gas mixtures containing 3 % of oxygen, the number of cells, synthesizing eGFP+ before and after the transfection procedure, was on average 2.58 times higher in the nitrogen-based mixture and 1.37 times higher in the argon-based mixture than in control groups from the CO 2 –incubator. Conclusions. The cul­ tivation of human WJ-MSC under physiological oxygen tensions allowed an increase in the percentage of transfected cells, and is promising to be used as a method for optimization of transfection.