Fig. 6

Human placental extract (HPE) suppresses passive cutaneous anaphylaxis reaction. The right ear of BALB/c mouse was injected i.d. with 100 ng HPE, and the left ear was injected with an identical volume of PBS. After 24 h, both ears received 0.4 μg IgE in 10 μL PBS. The PCA reaction was induced 24 h later by an intravenous injection of 10 μg DNP-30–40-HSA and 2% Evans blue in 200 μL PBS. Thirty minutes after the provocation, the ears were collected and processed by tissue homogenizer after the mouse were sacrificed. A 30 min after the dye injection, ears were excised and photographed (left panel, depicting ears from one mouse), and dye extravasation was quantified and plotted (right panels). Each line represents data from an individual mouse, and bars indicate the average values. B Alternatively, ear tissue sectioning was prepared. Toluidine blue staining was used to identify tissue mast cells. Resting or degranulating mast cells could be visualized. Green arrows, degranulating cells; red arrows, resting cells. Numbers of resting and degranulating mast cells in ear tissues were enumerated and plotted. The percentages of degranulating mast cells in the PBS-treated ears versus HPE–treated ears were 66.6 ± 12.18% versus 67.8 ± 14.7% (4 h-pretreatment), 64.8 ± 14.4% versus 34.1 ± 12.8% (8 h-pretreatment) and 65.7 ± 9.45% versus 37.7 ± 16.3% (16 h-pretreatment), respectively (five mice; mean ± SEM; P = 0.0004). Data are shown as mean ± SEM (n = 5) of three separate experiments.*P < 0.05, using the unpaired Student t test for statistical significance