Copper nanoparticles suppresses nitric oxide production in macrophages (CAM5P.234)

Copper and copper oxide nanoparticles (CuNP) have been utilized as anti-microbial agent, metal catalyst, diet supplement, high thermal conductive material, lubricant additive, among others. Although the uses of CuNP are relatively new, there is an increasing interest to know their immunotoxicology. CuNP have shown to induce one of the most potent acute inflammatory reactions among several types of nanoparticles. Recently, in a pulmonary infection model, it was demonstrated that mice, which had been previously exposed to CuNP, presented an impaired bacterial clearance. These effects were due to a reduction in macrophage function; however, the precise molecular mechanism underlying these effects is still unknown. Here, we described the effects of CuNP in the response of peritoneal macrophages against microbial products. Transmission electron microscopy (TEM) data showed that CuNP were rapidly internalized by macrophages. The internalization of the particles induced a significant reduction of cell viability in comparison with other nanoparticles. The challenge with CuNP inhibited LPS-mediated nitric oxide (NO) production in a dose dependent manner. These results showed that CuNP modulate the expression of a key inflammatory mediator that is crucial to eliminate bacterial infection.