Fig. 3
AKT pathway activation and the expression of CTGF, IGF-2 and bFGF in the DC tissue. DC samples were stained with antibodies recognizing SMA, phosphorylated AKT at T308 (pAKT), collagen IV (CoIV), keratin15 (K15), CTGF, IGF-2, bFGF and Ki67 as indicated on the panels. Nuclei were counterstained with DAPI. pAKT was detected in blood vessels (a,b; blue arrows), sweat gland acini (b; violet arrows) and sweat gland ducts (b; white arrows). Sweat gland acini were identified as containing characteristic K15-positive basal epithelium, which is encompassed by CoIV-positive basement membrane (BM; c; violet arrows). Sweat gland ducts (c; white arrows) and blood vessels (c; blue arrows) are negative for K15 and contain weakly CoIV-positive BM. The expression of CTGF (d), IGF-2 (e) and bFGF (f) was detected using qPCR in DC (n = 8) and NPF (n = 4) samples. Center lines show the medians; box limits indicate the 25th and 75th percentiles; whiskers extend 1.5 times the interquartile range from the 25th and 75th percentiles. The expression of all three growth factors was increased in DC samples when compared to NPF. K15-positive sweat gland acini synthetize CTGF (g, h; violet arrows) whereas ducts (h; white arrows) and blood vessels (g, h; blue arrows) are negative for CTGF. Sweat gland ducts contain dividing Ki67-positive cells (i; white arrows) while CTGF-expressing SMA-positive acini are not proliferative (i; violet arrow). IGF-2 is expressed throughout the DC tissue (j-l). The color-split images of (j) for IGF-2/DAPI (k) and SMA/vWF (l) are presented to underline the uniform distribution of IGF-2 expression in the DC tissue. bFGF co-localizes with vWF and thus is expressed in the endothelium of the DC-associated blood vessels as presented by cross (m) and longitudinal sections (n) of blood vessels. Scale bars: 50 μm. AKT Ak mouse strain thymoma-associated, bFGF basic fibroblast growth factor, CTGF connective tissue growth factor, DC Dupuytren’s contracture, IGF-2 insulin-like growth factor 2, NPF normal palmar fascia, qPCR quantitative polymerase chain reaction, SMA smooth muscle actin