Fig. 4

Equine MSC secrete factors that depolarize bacterial cell membranes, but do not cause immediate cell death. a Incorporation of NPN into depolarized E. coli membranes (left panel) and S. aureus membranes (right panel) treated with MSC CM compared to high concentrations of compounds known to depolarize bacterial cell membranes. b CFU per ml of E. coli (left panel) and S. aureus (right panel) following culture at 4 °C with bactericidal compounds polymixin B (PMB), nisin or MSC CM. *P < 0.05 c NPN incorporation by depolarized E. coli (left panel) and S. aureus (right panel) membranes as measured by fluorescent emission at 444 nm. Bacteria were treated with DMEM, MSC CM, and MSC CM fractioned by size of secreted factors. Different letters indicate statistically significant (P < 0.05) differences. n = 3. CFU colony-forming units, CM conditioned medium, DMEM Dulbecco’s modified Eagle medium, MSC mesenchymal stromal cells