3-nitrotyrosine and Ascites

The ability of macrophages to produce reactive nitrogen species, particularly nitric oxide (NO) is correlated with an enhanced microbicidal or tumoricidal activity during pathogenic or tumoral invasion, respectively. NO reacts in water with oxygen and its reactive intermediates to yield, among others, nitrite and nitrate, which are relatively, stable anions. In this study, we show the varying concentrations of nitrite and nitrate present in different body fluids during AK-5 tumor growth and regression in Wistar rats. We have followed the tumor progression profile and the corresponding levels of nitrite and nitrate present in three major body compartments: the tumor mass; the serum which is the intermediary site; and the peritoneal compartment which is the priming ground for the macrophages. We are thus able to show that the status of the tumor has a direct correlation with macrophage activation and motility to different sites in the body. We also demonstrate after in vitro coculture, that the levels of nitrite and nitrate secreted by the macrophages correlate with their cytocidal capacity.

Topics: Animals; Ascites; Ascitic Fluid; Blotting, Western; Cells, Cultured; Coculture Techniques; Histiocytoma, Benign Fibrous; Macrophage Activation; Macrophages; Neoplasm Transplantation; Neoplasms, Experimental; Nitrates; Nitrites; Proteins; Rats; Rats, Wistar; Skin Neoplasms; Tyrosine

In the present study, we used IL-6 knock-out mice (IL-6KO) to evaluate a possible role of IL-6 in the pathogenesis of non-septic shock induced by peritoneal injection of zymosan. A severe inflammatory response characterized by peritoneal exudation, high peritoneal levels of nitrate/nitrite, and leukocyte infiltration into peritoneal exudate was induced by zymosan administration in wild-type control (WT) mice. This inflammatory process coincided with the damage to the lung and small intestine, as assessed by histological examination. Lung, small intestine and liver myeloperoxidase (MPO) activity, indicative of neutrophil infiltration and lipid peroxidation, were significantly increased in zymosan-treated WT mice. Peritoneal administration of zymosan in the WT mice also induced a significant increase in the plasma levels of nitrite/nitrate and in the levels of peroxynitrite, 18 hours after zymosan challenge. Immunohistochemical examination demonstrated a marked increase in the immunoreactivity to nitrotyrosine in the lung of zymosan-treated WT mice. Zymosan-treated IL-6KO showed significantly decreased mortality and inhibition of the development of peritonitis. In addition, IL-6KO mice showed significant protection from the development of organ failure, since tissue injury and MPO was reduced in the lung, small intestine and liver. Furthermore, a significant reduction of suppression of mitochondrial respiration, DNA strand breakage and reduction of cellular levels of NAD+ was observed in ex vivo macrophages harvested from the peritoneal cavity of IL-6KO mice subjected to zymosan-induced non-septic shock. In vivo treatment with anti-IL-6 (5,000 ng/day per mouse, 24 and 1 hour before zymosan administration) significantly reduced the inflammatory process. Taken together, the present study clearly demonstrates that IL-6 exerts a role in zymosan-induced non-septic shock.

Topics: Animals; Antibodies, Monoclonal; Ascites; Ascitic Fluid; DNA Damage; Energy Metabolism; Injections, Intraperitoneal; Interleukin-6; Intestine, Small; Leukocyte Count; Lipid Peroxidation; Liver; Lung; Macrophage Activation; Macrophages, Peritoneal; Mice; Mice, Inbred C57BL; Mice, Knockout; Multiple Organ Failure; NAD; Neutrophils; Nitrates; Nitrites; Oxidative Phosphorylation; Peritonitis; Peroxidase; Shock; Tyrosine; Zymosan