Role of mast cells in zymosan-induced peritoneal inflammation in Balb/c and mast cell-deficient WBB6F1 mice

Zymosan-induced peritonitis was investigated in mast cell-deficient WBB6FI mice and in Balb/c mice pretreated with mast cell stabilizer (cromolyn) or antagonists of histamine receptors (mepyramine, triprolidine, cimetidine, o r ranitidine). The inherited mast cell deficiency in W/W-v knockouts of WBB 6F1 mice impaired significantly the level of histamine and plasma exudation (measured 30 min after stimulation) as well as the influx of exudatory leu kocytes, accumulation of plasma and exudate chemoattractants, and the relea se of proinflammatory cytolkines (TNF-alpha, IL-1 beta, and IL-6) measured at 6 h of inflammation. All of those factors were fully restored after sele ctive intraperitoneal reconstitution of W/W-v nlice with bone marrow-derive d mast cells from their control +/+ counterparts. Cromolyn pretreatment of Balb/c mice reduced exclusively the early plasma exudation and histamine in flux. Blocking of histamine receptors inhibited not only the early plasma e xudation hut also temporarily diminished primary leukocyte influx and level s of MCP-1 and IL-I beta. In conclusion, mast cells play an important role ill the initiation of zymosan-induced peritonitis and modulate its further course.