Figure 5

Wharton's jelly-derived mesenchymal stem cell conditioned medium promotes cell proliferation in an in vivo mouse wound healing model. A BALB-c mouse wound healing model was used and animals were wounded and treated as described previously. Animals received one dose of bromodeoxyuridine (BrdU) intraperitoneally 24 hours before harvesting of wounds. Four animals were included in each group, and four wounds were performed per animal (total of 16 wounds in each group). Cutaneous tissue specimens were stained for BrdU in both groups, control (A) and treatment (B). Enhanced magnification (40×) of the above microscopic images were included for nonconditioned medium-treated (C) and Wharton's jelly-derived mesenchymal stem cell conditioned medium (WJ-MSC-CM)-treated normal skin fibroblasts (D) to examine in further detail the increase in cell number or stained nuclei (black arrows, BrdU-positive cells) in the WJ-MSC-CM-treated wounds, compared with controls. This denoted that WJ-MSC-CM stimulated cell proliferation in vivo (E, F). Together, these results suggest that WJ-MSC promoted wound healing and repair by one-way paracrine signaling in an in vivo preclinical model. *P ≤ 0.05, **P ≤ 0.01. Error bars represent the 95% confidence interval. Arrows, BrdU-positive nuclei; arrowheads, BrdU-negative nuclei. HPF, high-power field.