Inhibition of tryptase and chymase induced nucleated cell infiltration by proteinase inhibitors

To investigate the ability of proteinase inhibitors to modulate nucleated cell infiltration into the peritoneum of mice induced by tryptase and chymase.

Human lung tryptase and skin chymase were purified by a similar procedure involving high salt extraction, heparin agarose affinity chromatography followed by S-200 Sephacryl gel filtration chromatography. The actions of proteinase inhibitors on tryptase and chymase induced nucleated cell accumulation were examined with a mouse peritoneum model.

A selective chymase inhibitor Z-Ile-Glu-Pro-Phe-CO2Me (ZIGPPF) was able to inhibit approximately 90 % neutrophil, 73 % eosinophil, 87 % lymphocyte and 60 % macrophage accumulation induced by chymase at 16 h following injection. Soy bean trypsin inhibitor (SBTI), chymostatin, and alpha1-antitrypsin showed slightly less potency than ZIGPPF in inhibition of the actions of chymase. While all tryptase inhibitors tested were able to inhibit neutrophil, eosinophil, and macrophage accumulation provoked by tryptase at 16 h following injection, only leupeptin, APC366, and aprotinin were capable of inhibiting tryptase induced lymphocyte accumulation. The inhibitors of tryptase tested were also able to inhibit tryptase induced neutrophil and eosinophil accumulation at 6 h following injection. When being injected alone, all inhibitors of chymase and tryptase at the concentrations tested by themselves had no significant effect on the accumulation of nucleated cells in the peritoneum of mice at both 6 h and 16 h.

Proteinase inhibitors significantly inhibited tryptase and chymase-induced nucleated cell accumulation in vivo, and therefore they are likely to be developed as a novel class of anti-inflammatory drugs.