Mitigation of Cu(II)-induced damage in human blood cells by carnosine: An in vitro study

Abstract Copper (Cu) is an essential micronutrient but human exposure to high level of this metal results in adverse health effects. Oxidative stress is assumed to play a major role in the mechanism of Cu-induced toxicity. The protective role of carnosine, an antioxidant and antiglycating agent, was examined against Cu-induced toxicity in isolated human blood cells. Red blood cells (RBC) were treated with 0.5 mM copper chloride (CuCl2), a Cu(II) compound, either alone or after treatment with carnosine. Incubation of RBC with CuCl2 increased protein oxidation, lipid peroxidation, methemoglobin formation and lowered glutathione content. The antioxidant defense system was impaired and production of reactive oxygen (ROS) and reactive nitrogen species (RNS) was enhanced. Pre-incubation of RBC with carnosine protected the cells against CuCl2-induced oxidative damage. It restored the activities of several antioxidant, membrane-bound and metabolic enzymes, decreased the generation of ROS and RNS, enhanced the antioxidant power of cells and prevented inactivation of plasma membrane redox system. Carnosine also protected human lymphocytes from CuCl2-induced DNA damage. The protective effects of carnosine were concentration-dependent while carnosine itself did not exhibit any adverse effect. Carnosine can, therefore, be used as a possible chemoprotectant against the harmful effects of this extremely redox active metal.