Figure 4. Intravital imaging of the tongue cancer model.

A. Schematic drawings of the tongue holding device, animal set up for intravital imaging, and primary tumor mass growing in the tongue. B. Intravital microscopy of tongue cancer at the primary site. Hela-O3 cells expressing H2B-GFP were transplanted into the tongue submucosa. Before imaging, a 70 kDa dextran was injected systemically to reveal stromal cells. A Z-scan was performed by using two-photon microscopy (60× water immersion lens, NA 1.2, Olympus). The same area was imaged using either 750 nm (upper panels) or 930 nm (lower panels) as excitation wavelengths. Both conditions revealed tumor cells (green) and stromal cells (red). However, the excitation at 750 nm revealed the tongue parenchyma (cyan), whereas the excitation at 930 nm revealed components of the extracellular matrix and myosin filaments from the muscle fibers (cyan). Scale bars, 20 μm.