Cell counting kit 8 cck 8 assay

A rapid and highly sensitive assay based in the chromogenic reaction of WST-8 (a tetrazolium salt), Cell Counting Kit-8 (CCK-8) assay (Bioworld Technology, Nanjing, China), was used to evaluate cell proliferation and cytotoxicity. Cells at a density of 5 $\times$ 10⁴ cells/mL (100 µL/well) were seeded in 96-well plates and incubated overnight under 5% CO2 at 37 °C, followed by exposure to a series of concentrations of resveratrol (50, 100, 150, 200, and 250 µM). At the same time, a group only containing culture medium was set as blank control. Each group had six biological repeats. After dosing for 24, 48, and 72 h, the cells were washed and then fresh medium (100 µL) supplemented with 10 µL CCK-8 solution (0.5 mg/mL) was added to each well. After incubated in the dark for 2 h at 37 °C, the optical density at 450 (OD450) of each well were measured by plate reader (Synergy H4: Bio-Tek, Winooski, VT, USA). The results are presented as mean ± standard deviation (SD). The survival rate of control cells treated with 0 M resveratrol was set as 100%. Cell viability was calculated using the following Equation (1): $\mathrm{C}\mathrm{e}\mathrm{l}\mathrm{l} \mathrm{v}\mathrm{i}\mathrm{a}\mathrm{b}\mathrm{i}\mathrm{l}\mathrm{i}\mathrm{t}\mathrm{y}\left(\%\right)=\frac{\mathrm{d}\mathrm{o}\mathrm{s}\mathrm{i}\mathrm{n}\mathrm{g} \mathrm{c}\mathrm{e}\mathrm{l}\mathrm{l} \mathrm{O}\mathrm{D}-\mathrm{b}\mathrm{l}\mathrm{a}\mathrm{n}\mathrm{k} \mathrm{O}\mathrm{D}}{\mathrm{c}\mathrm{o}\mathrm{n}\mathrm{t}\mathrm{r}\mathrm{o}\mathrm{l} \mathrm{c}\mathrm{e}\mathrm{l}\mathrm{l} \mathrm{O}\mathrm{D}-\mathrm{b}\mathrm{l}\mathrm{a}\mathrm{n}\mathrm{k} \mathrm{O}\mathrm{D}}\times 100$