Population doubling time (PDT) comparison between human and canine mesenchymal stem cells (MSCs) in vitro. The population doubling time of human and canine MSCs was measured. The Y-axis represents population doubling time (hr), and the X-axis indicates the passage number. The filled box shows the PDT of human MSCs, analyzed from passage 0 to passage 15 (n = 3). The open box indicates the PDT of canine MSCs at each passage number, passage 0-12 (n = 4). Symbols are presented as mean ± SEM. The significance of differences was determined using one-way ANOVA with Tukey’s post-hoc test. a,b,cp < 0.05.