Cell cycle analysis was carried out using propidium iodine (PI) staining. In short, after exposure to 90SrCl2, cells were detached by trypsin incubation, washed twice and counted. 300,000 cells were fixed in 70% ethanol and stored at −20 °C for at least one hour. Cells were then centrifuged 8 minutes at 400 g and the pellet was re-suspended with a sodium citrate solution containing 0.2% Triton X-100, 100 μg.mL−1 RNAse and 50 μg.mL−1 PI (Sigma) and incubated 30 minutes at 37 °C in the dark. Stained cells were then analyzed on a FACS Canto II (BDIS, Le Pont-de-Claix, France) with the acquisition of at least 10,000 events per condition.
Phenotypic analysis of rat BMSCs was performed using the following directly coupled antibodies: anti-IgG1-FITC, anti-IgG2a-PE, anti-CD44-FITC, anti-CD45-FITC, anti-CD90-PE, anti-CD73-alexa647 (all from BD Pharmingen, Le Pont-de-Claix, France) and anti-CD34-PE (Santa Cruz Biotechnologies). At the first passage, aliquots of 200,000 cells were washed twice in PBS and incubated for 20 minutes in the presence of the indicated antibodies at pre-defined concentrations. Cells were then washed twice and analyzed.
Phenotypic analysis of rat BMSCs was performed using the following directly coupled antibodies: anti-IgG1-FITC, anti-IgG2a-PE, anti-CD44-FITC, anti-CD45-FITC, anti-CD90-PE, anti-CD73-alexa647 (all from BD Pharmingen, Le Pont-de-Claix, France) and anti-CD34-PE (Santa Cruz Biotechnologies). At the first passage, aliquots of 200,000 cells were washed twice in PBS and incubated for 20 minutes in the presence of the indicated antibodies at pre-defined concentrations. Cells were then washed twice and analyzed.