Mast cells are activated, and substance P and histamine levels are increased, in ligation-induced acute pancreatitis in mice and rats.

<p>A) Toluidine blue (0.1%) staining of mouse pancreas and lung tissue cryosections (scale bar = 200 µm) showed increased mast cell activation 48 hrs after pancreatic duct ligation (PD). Black arrows show quiescent mast cells while red arrows indicate mast cell activation (degranulation). ELISA analysis showed increased substance P in mouse pancreas homogenates and increased histamine in mouse plasma 48 hrs after PD compared to sham control group. B) Toluidine blue (0.1%) staining of rat pancreas and lung tissue cryosections (scale bar = 200 µm) showed increased mast cell activation 48 hrs after PD (also at 5 hrs in the pancreas). Black arrows show quiescent mast cells while red arrows indicate mast cell activation (degranulation). ELISA showed increased pancreatic substance P and plasma histamine in rats 48 hrs after PD. Data are mean ± SEM; Student's t-test; asterisk (*) indicates significance compared to sham control group, p<0.05.