Figure 2

The distribution of α-smooth muscle actin (SMA)-immunoreactive cells, TNC molecule, and TNC-expressing cells at Day 1 (a and b), Day 3 (c, d, and e), and Day 5 (f, g, and h). ISH for TNC (b, g, and i), immunoreactivity for SMA (h), double labeling for immunoreactivity of SMA and ISH for TNC mRNA (e), double immunoreactivity for TNC and SMA in the same tissue section (a, c, d, and f). At Day 1 (a), deposition of TNC can be detected (brown), but only vascular cells are immunoreactive for SMA (blue), although several interstitial cells express TNC mRNA (b). At Day 3 (c), SMA-immunoreactive interstitial cells (blue) appear in the TNC-immunoreactive area (brown) at the border zone. d, High-power view of c. Double labeling for SMA immunoreactivity and TNC mRNA (e) shows that most TNC-producing cells (purple) are negative for SMA (brown) and most SMA-immunoreactive cells are also not expressing TNC. At Day 5, TNC immunoreactivity (brown in f) and cells positive for TNC mRNA (g) are seen at the periphery of the necrotic mass in the granulation tissue. Some SMA-immunoreactive cells (blue in f) are seen in the TNC-positive area but distributed over a broader area (brown in h; compare with g). High-power view of ISH for TNC (i) and immunoreactivity for SMA (j) of serial sections shows that the same cells are positive for both SMA and TNC signals (arrows). Bars: a, 50 μm for panels b and c; e, 50 μm for panels d, e, i, and j; g, 50 μm for panels f, g, and h). Abbreviations: inf, infarcted area; int, intact area; nec, necrotic mass; gr, granulation tissue.