I propidium iodide

For the viability/cytotoxicity assessment, the cells were stained with РI (propidium iodide) (Sigma-Aldrich, USA) and FDA (fluorescein diacetate) (Sigma-Aldrich, USA) before differentiation and after 3, 7 and 14 days of adipogenic differentiation. Detailed description of the method was presented in previous studies^{40 (link),41 (link)}. The number of dead and living ADSCs in different groups was counted using inverted fluorescent microscopy AxioObserver A1 and ZEN 2012 software (Carl Zeiss). The cell viability was calculated as the ratio of living cells to the total number of cells and was expressed as a percentage according to the formula: $$\mathrm{Viability}=\left(\mathrm{number}\mathrm{of}\mathrm{living}\mathrm{cells}/\mathrm{total}\mathrm{number}\mathrm{of}\mathrm{cells}\right)\times 100\%$$

Standard protocol was used for the FDA and PI assay [29 (link)]. The cells were stained with РI (propidium iodide) (Sigma-Aldrich, USA) and FDA (fluorescein diacetate) (Sigma-Aldrich, USA) after 24 h and 72 h in culture. PI does not penetrate into living cells; therefore, it stains only those in which the integrity of the cell membrane is broken. FDA is not a fluorescent molecule, but when penetrated into living cells, it is converted into a fluorescent form, fluorescein. The number of dead and living cells in different groups was counted using fluorescence microscopy (FITC and Texas Red filters; Carl Zeiss, Germany).
Viability was calculated as the ratio of living cells to the total number of cells and was expressed as a percentage according to the formula: $\begin{array}{c}\text{cell\hspace{0.17em}viability}=\left(\frac{\text{number\hspace{0.17em}of\hspace{0.17em}living\hspace{0.17em}cells}}{\text{total\hspace{0.17em}number\hspace{0.17em}of\hspace{0.17em}cells}}\right)\times 100\%.\end{array}$