Thrombin pretreatment promotes the adhesion of MSCs to the culture plastic. A: Aliquots (2 × 104/100 μl) of MSCs or MSCs were pre-treated with thrombin (4 U/ml) for 24 h were seeded into a 96-well culture plate for spontaneous adhesion for 1 h (a and b), the non-adherent cells was then washed and discarded (c and d). After incubated with MTT at 37°C for three to four hours, the adherent cells were stained by MTT (e and f). B: The crystallized formozan was dissolved in DMSO and OD values at a wavelength of 490 nm were detected. CTR: MSCs cultured without thrombin; TH: MSCs treated with thrombin. **P <0.01. The results here are representative of the data from three individual experiments. CTR, Control; DMSO, Dimethyl sulfoxide; MSCs, mesenchymal stem cells; MTT, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide; OD, Optical density.