The presence of α-smooth muscle actin (SMA) expression myofibroblast pre- and post-wounding. Skin of connective tissue growth factor/enhanced green fluorescent protein (CTGF/E-GFP) hemizygous mice (pre-wounding, day 0, or post-wounding, day 3 or day 7) was fixed, sectioned, and stained with 4',6-diamidino-2-phenylindole (DAPI) to detect nuclei or anti-α-SMA antibody to detect myofibroblasts (lefthand panels, 10 × magnification of dermal tissue; righthand panels, 40 × magnification of dermal tissue). Quantitiation of myofibroblasts was performed as described in Methods. Note that α-SMA expression was absent in the epidermis (day 0); however, a small number of dermal cells were positive for α-SMA expression. Post-wounding, myofibroblasts appeared within granulation tissue. *, significant induction compared to day 0 unwounded skin. Representative data from four wounds from four separate animals per timepoint is shown.