Figure 1

Lung metastases in WT and MMP-13 KO mice after intravenous injection of B16BL6 melanoma cells. (A) Representative macroscopic views of lung metastases and evaluation of lung weight and number of metastatic foci on the lung surface at 3 weeks after the injection of 5 × 10⁴ melanoma cells into WT and MMP-13 KO mice (n=15 per group). Note that metastatic foci are seen as black nodules on the surface of the lungs. Metastatic foci were counted by stereoscopic microscope. Bars, mean±s.d. ^**P<0.01. (B) Representative microscopic views of the lung sections and evaluation of number of metastatic foci and area ratio of metastatic nodules in WT and MMP-13 KO mice (n=7 per group). Paraffin sections stained with haematoxylin and eosin show that metastatic foci are seen as haematoxylin-positive blue-coloured lesions. The number per lung was counted, and area ratio of metastatic foci to whole lung was calculated using Image J software. Bars, mean±s.d. ^*P<0.05; ^**P<0.01.