Effect of oxidized dextrans on NO synthase and arginase activities of mouse macrophages

We studied the effect of oxidized dextrans with molecular weights of 30-35 kDa and 60-65 kDa on NO synthase and arginase activities of mouse peritoneal macrophages in vivo and in vitro. Oxidized dextrans irrespective of molecular weight shifted the NO synthase/arginase balance towards predominance of NO production under in vivo and in vitro conditions. Administration of the test compounds to intact mice considerably increased NO synthase activity, while culturing of peritoneal macrophages in the presence of modified dextrans reduced arginase activity in these cells. These effects of oxidized dextrans create conditions for predominant stimulation of Th1-mediated immune reactions.