DIETARY COPPER DEFICIENCY INCREASES THE MAST-CELL POPULATION OF THE RAT

Mast cell-released histamine has been implicated In the enhanced acute inflammatory response of copper-deficient rats. The present study exa mined possible changes in the copper-deficient mast cell which may acc ount for increased macromolecular leakage and edema formation. Mast ce ll populations were determined in the cremaster muscle of copper-adequ ate and copper-deficient rats. Total histamine content, unstimulated h istamine release and concentration-dependent histamine release with th e mast cell secretagogue compound 48/80 were also determined in isolat ed peritoneal mast cells. A significantly higher number of mast cells were found in the cremaster muscle of the copper-deficient rats (78 +/ - 7 cells/5 mu m section) than in the copper-adequate controls (51 +/- 4). Total histamine content per cell as well as unstimulated and stim ulated release of the inflammatory mediator per cell were not differen t between the groups. The results suggest that dietary copper deficien cy increases the mast cell population but does not alter the mast cell histamine content or sensitivity to degranulation in the rat. This in crease in the number of mast cells may be a mechanism by which acute i nflammation is enhanced in copper deficiency.