Figure 5

Comparison of ΔΨ _m of bone marrow-derived mesenchymal stem cells (BMMSCs) and bacterial viability in co-culture of BMMSCs with reference strains Pseudomonas aeruginosa ATCC9027, Staphylococcus aureus ATCC6528, and Staphylococcus epidermidis ATCC12228. BMMSC line 407 was used to determine the bacterial growth kinetics within 4 and 24 hours of infection. P. aeruginosa ATCC9027, S. aureus ATCC6538, and S. epidermidis ATCC12228 were inoculated in an indicated initial inoculum (0 hours). Medium without BMMSCs was used as a control. Series of 10-fold dilutions were prepared from each sample, and the number of colony-forming units (CFU) was determined from at least two different 10-fold dilutions per sample. (a) All of the bacterial strains grew exponentially within 24 hours of infection. (b) There were some differences in the growth rate of bacteria between different bacterial strains within the first 4 hours of infection. (c) At this time point, initially slowly proliferated S. epidermidis ATCC12228 also showed efficient bacterial growth. (d) The analysis of ΔΨ_m was performed in parallel with the determination of CFUs after 4 hours of infection. The fluorescent 595 nm/535 nm ratio of JC-10 was used to determine ΔΨ_m, and the 595 nm/535 nm ratios of infected BMMSCs were compared with controls. Results are indicated as mean ± standard deviation of four independent replicates. *Two-sample t test P values of less than 0.05 when compared between control BMMSCs and infected BMMSCs; **two-sample t test P values of less than 0.01 when compared between control BMMSCs and infected BMMSCs; ***two-sample t test P values of less than 0.001 when compared between control BMMSCs and CCCP-treated BMMSCs. ΔΨ_m, mitochondrial inner membrane potential; CCCP, carbonyl cyanide m-chlorophenylhydrazone; JC-10, enhanced 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide.