Collagen producing FMC are recruited to maternal skin wounds as early as day 1.

<p>(<b>A</b>) Representative BLI images across wound healing. All animals were post-partum WT females but those labeled WT FMC had produced only WT fetuses whereas those labeled Col1a2 FMC had produced Col1a2 transgenic fetuses. Red circles = ROI kept constant over time for comparison of measurements. Signal was absent in unwounded skin (day 0). (<b>B</b>) BLI signal, represented as total flux (photons/s), was tracked over the course of wound healing. Signal was always higher in Col1a2 FMC animals (receiving transgenic FMC) (ANOVA on D7 or D14 cohorts p = 0.01). Maximal signal was observed day 1 after wounding. (<b>C</b>) Box and whisker plots represent the median and range of signal produced from wound regions at day 1. Signal was more intense in WT animals receiving transgenic FMC (p<0.01). (<b>D</b>) Animals with high BLI signal (>99^th percentile of background). In the Col1a2 FMC group, 9/43 animals compared to 1/43 animal in the WT FMC group had high BLI signal (Fisher exact p = 0.01). (<b>E</b>) Microchimerism was confirmed in wound tissue from high BLI animals by the detection of Y-chromosome+ve fetal cells. (<b>E-a</b>) Male wound positive control. White arrows point to examples of nuclei with Y-chromosome signal. (<b>E-b</b>) Representative image of a single Y-chromosome+ve fetal cell (white arrow) found amongst maternal dermal cells in the wound center. Scale bars represent 10 µm.