Fig. 5.

Characterization of BMP components in injury-induced lesions. a, b Typical image of BMP4 staining of early (a) and later (b) lesions. Note that BMP4 was upregulated but more or less evenly in the early lesion. However, a BMP4 gradient was apparent from the condensation stage onward, i.e., high BMP4 signal was located mostly in the inner core, and there was an obvious gradient (white arrow). c, d Typical image of BMPRII staining of early (c) and later (d) lesions. No obvious upregulation or gradient for BMPRII throughout the lesion. e, f Typical image of pSMAD1/5 staining of early (e) and later (f) lesions. Note that pSMAD1/5 showed a similar pattern as that of BMP4. Bar = 50 μm