Figure 5

Toluidine staining to confirm mast cell (MC) expression. Significant increase in MCs toluidine count in arthritic mice with BC (SKG+4T1 and PyV MT+CII) versus nonarthritic (Balb/C+4T1 and PyV MT) BC models in (A) tumors (**P < 0.01), (C) lungs (***P < 0.001), and (E) bones (***P < 0.001; **P < 0.01). Significant increase in MCs toluidine staining was also observed in arthritic control (SKG and C57BL/6+CII) mice with no tumor as compared with nonarthritic (Balb/C mice with BC and spontaneous BC PyV MT mice) in (C) lungs (*P < 0.05) and (E) bones (*P < 0.05). We observed the same trend of MC expression with toluidine staining in tumors, lungs, and bones of arthritic versus nonarthritic BC models as in MCs tryptase staining (Figures 2 through 4). Representative images of toluidine staining in (B) tumors (200×), (D) lungs (400×), and (F) bones (400×) (six mice per experimental group and 10 fields per section per organ). Purple-blue staining represents MCs toluidine expression.