Figure 5. Fibroblast-specific Smad2/3 deletion reduces the number of activated myofibroblasts in vivo.

(A) Experimental schematic whereby mice were subjected to TAC injury for 7 days. Mice were fed tamoxifen-laden chow 48 hours before surgery and then until harvesting. EdU was injected into mice 24 hours and 4 hours before harvest. (B and C) Representative flow cytometry plots of isolated EGFP⁺ interstitial cells (rightward scatter) from hearts of the indicated genotypes of mice. (D) The ratio of total GFP⁺ activated fibroblasts normalized to CD31⁺ cells from the heart taken from the indicated genotypes of mice after 1 or 4 weeks of TAC. Error bars represent SEM. n = 3 mice in each group. *P < 0.05 versus Postn^MCM/+ R26^EGFP/+. P values were calculated with Student’s t test. (E and F) Representative immunohistological images and quantitation of the percentage of EGFP⁺ interstitial cells costained for EdU (white) according to the schematic in A. DAPI was used to show nuclei (blue). n = 3 mice in each group. *P < 0.05 versus Postn^MCM/+ R26^EGFP/+. P values were calculated with Student’s t test. Scale bars: 50 μm. (G) Quantitation of CD31-positive cells that were also EdU positive in heart histological sections from mice subjected to TAC of the indicated genotypes. Representative images of the CD31-positive cells with EdU staining along with GFP-positive fibroblasts from histological heart sections are shown in Supplemental Figure 6.