Modulation of P2X7 receptor expression in macrophages from mineral oil-injected mice

P2X(7) receptor activation is involved in a number of pro-inflammatory responses in macrophages and other immune cells. Their expression can be positively modulated with lipopolysaccharide (LPS) and TNF alpha, reinforcing their role during inflammation. We investigated the effect of substances capable of recruiting macrophages into the peritoneal cavity of mice (mineral oil and thioglycolate) on P2X(7) receptor expression and function, addressing whether these stimuli can interfere with multinucleated giant cell (MGC) formation. ATP-induced apoptosis, plasma membrane permeabilization and nitric oxide production. It was deomonstrated that mineral oil treatment reduces P2X(7)-dependent MGC formation, whereas thioglycolate treatment does not. Minearl oil treatment reduced P2X(7) receptor expression, down-modulating ATP-induced apoptosis, permeabilization and nitric oxide production. In conclusion, mineral oil down modulated P2X(7) expression and consequently P2X(7)-associated phenomena, but thioglycolate did not. These effects might be associated with the unpleasant side effects already described during long-term administration of mineral oil for cosmetic purposes or as a laxative and could be useful in understanding the mechanism of recycling and modulation of P2 receptors present in other situations of immunopathological interest. (C) 2007 Elsevier GmbH. All rights reserved.