Figure 4

Expression of mast cells (MCs) tryptase staining on bones. (A) Significant increase in MCs tryptase count in the bones of arthritic SKG mice challenged with 4T1 cells versus nonarthritic Balb/C mice injected with 4T1 cells (***P < 0.001) and in arthritic PyV MT mice induced with CII versus nonarthritic PyV MT mice (***P < 0.001). Significant increase in MCs tryptase also is observed in the bones of arthritic SKG mice with no tumor versus Balb/C mice with BC (*P < 0.05). Similarly, although not significant, we see the same trend in arthritic C57BL/6 mice induced with CII versus a spontaneous BC model of PyV MT mice with no arthritis. Representative images of tryptase staining in (B, C) bones taken at 400× magnification (six mice per experimental group and 10 fields per section). Brown staining represents MCs tryptase expression.