Fig. 3

Myocardial infarct size and interstitial collagen fiber content evaluated 2 weeks after surgery. a Images of ventricular myocardium stained with hematoxylin-eosin to show the regions of infarcted myocardium (200×). In the Sham group, the cytoplasm of the rabbit ventricular myocytes was uniformly stained pink, and the nuclei were stained blue-black. In the CME group, the infarcted areas were clearly evident around the arterioles, with edema, degeneration of peripheral myocardium, and infiltration of peripheral inflammatory cells. Compared with the CME group, the infarcted region was much smaller in the G-CSF group but similar in size in the AG490 group. Quantification of the size of the microinfarcted region as a proportion of the total area is shown in the graph on the right. Data are shown as means ± standard deviations of at least three independent experiments. **P < 0.01 vs. Sham group; ##P < 0.01 vs. CME group (one-way ANOVA with LSD post hoc test). b Images of ventricular myocardium stained with Masson trichrome to show the interstitial collagen fiber content (200×). The cardiomyocytes are stained red, and collagen is stained blue. Interstitial collagen content was notably higher in the CME, G-CSF, and AG490 groups than in the Sham group. The interstitial deposition of collagen was not as great in the G-CSF group as in the CME and AG490 groups. Interstitial collagen content (excluding collagen around blood vessels) as a proportion of the total area is quantified in the graph on the right. Data are shown as means ± standard deviations (n = 10/group, except n = 9 in the AG490 group). **P < 0.01 vs. Sham group; ##P < 0.01 vs. CME group (one-way ANOVA with LSD post-hoc test)