Increased activity of the intestinal mucosal mast cells in rats with multiple organ failure

Abstract

This study was undertaken to evaluate the changes in the activity of the intestinal mucosal mast cells (IMMC) in multiple organ failure (MOF). A rat model of MOF was induced by intraperitoneal injection of zymosan. Both the functional alterations and the pathological morphology of essential organs, such as small intestine, liver, kidney and the lungs, were evaluated. The concentrations of histamine and tumor necrosis factor alpha (TNF-alpha) in plasma and small intestinal tissue were detected by fluorimetric assay and enzyme-linked immunosorbent assay, respectively. The ultrastructural changes of the IMMC from the MOF rats were evaluated by transmission electron microscopy. Zymosan induced obvious inflammatory morphology and functional impairment in the essential organs of the rats that were indicative of the characteristic changes in MOF. There was a significantly decreased concentration of histamine in the intestinal tissue of the MOF rats when compared with the normal controls (8.67 +/- 1.16 vs 11.63 +/- 1.97 ng/g protein, P < 0.01), whereas the plasma histamine concentration showed no significant changes. The concentration of TNF-alpha was elevated significantly in both the intestinal tissue and plasma of MOF rats. Furthermore, both the increased number and level of degranulation of the IMMC in the gut tissue was marked in MOF rats. The results suggest that the histamine and TNF-alpha released from activated IMMC play an important role in the development of MOF.