Fig. 8: OT exerted an anti-inflammatory response by inhibiting mast cell degranulation.

Morphology of hematoxylin and eosin (HE)-stained (a) and toluidine blue (TB)-stained (b) hind paw after the s.c. injection of saline or 5% formalin (100 µL) into the hind paw. Scale bar in (A), 50 µm. Scale bar in (B), 10 µm and 5 µm (in magnified image). c The subcutaneous tissue thickness measured using the HE-stained hind paw slices (n = 6–10 slices from 3 to 5 rats, each). **P < 0.01 vs. Saline s.c. + Saline s.c. ^##P < 0.01 vs. Saline s.c. + Formalin s.c. d Number of mast cells in subcutaneous tissue either granulated or degranulated was manually counted (n = 10 slices from 5 rats, each). **P < 0.01 vs. Saline s.c. + Formalin s.c. e Granulated and degranulated mast cell captured by transmission electron microscope (TEM) after formalin injection. N, nucleus. Red arrow heads indicate the granules that were degranulated from a mast cell. Scale bars, 5 µm. See also Supplementary Fig. 9.