MTT Dye Reduction Assay for Cell Viability

MTT dye reduction assay (Sigma, St.Louis, Mo, USA) was carried out to detect the cell viability as previously reported (Dai & etal, 2012 (link)). Briefly, cells were seeded into a 96-well plate at a density of 1 × 10⁵ cells/well, cultured for 12 h, then treated with LPS at a concentration of 300 μ g/mL for 24 h, and then treated with MSC-exosomes for 24 h. At the end of the treatment, 10 μ L (50 μ g) of the MTT solution was added into the cells and incubated for another 4 h. Two hundred microliters of dimethylsufloxide (DMSO), was added to each well after removal of the supernatant. After shaking for 10 min, cell viability was measured at an absorbance wavelength of 490 nm using an Enzyme-labeling instrument (Multiskan. Go, Thermo Scientific, Ratastie, Finland).