Figure 1

Photomicrographs of different developmental steps of canine muscle cell culture. A, B, C show cells kept under proliferation conditions from 2 to 6 days after harvesting. D, E, F show cells kept under differentiation conditions from 8 to 21 days after harvesting. A: a few small blastoid, circular cells are visible. B and C: typical morphology of proliferating mesenchymal cells. D and E: fusion of cells and formation of myotubes. At this stage spontaneous contraction of the cells can occur. F: finally differentiated multinucleated myotube. (All photomicrographs at 200-fold magnification; except 1D, taken at 100-fold magnification; bar = 100 μm).