Effect of dietary copper nanoparticles versus one copper (II) salt: Analysis of vasoreactivity in a rat model.

BACKGROUND: Vascular defects in the mechanical properties of aorta and muscular arteries have been previously reported in animals with copper-deficient feed. However, the interaction between copper nanoparticles (CuNPs) and mechanical properties of arteries has not been reported. Hence, the present study was aimed to evaluate the effect of copper nanoparticles on the vasoreactivity of rat isolated thoracic arteries.

METHODS: In this study, 5 week old male Wistar rats were fed a copper-adequate diet (CuA, 6.5mg copper/kg diet), copper-deficient diet (CuD) and copper-modified diets, enriched with copper as a salt (CuS) and as copper nanoparticles (CuNPs) of 40-60nm in diameter.

RESULTS: There was a strong relationship between CuNPs and CuS administration in the tensile strength of the thoracic aorta subjected to phenylephrine treatment in the concentration range of 10-7 -10-5 M. This was also seen between CuNPs and the control diet in the same concentration ranges. In addition vasodilation induced by acetylcholine at the concentration range of 10-7 -10-5 M was significantly reduced in CuD and NPs feed animals. In CuNPs fed rats, activities of Cu,Zn-SOD, CAT and copper concentration in cardiomyocytes were not influenced when compared with CuS control. In contrast, in CuS-low diet the activities of studied enzymes and copper concentration were pointing towards copper deficiency.

CONCLUSIONS: Our results demonstrate for the first time that the observed effects of copper administration in the form of NPs are attributed mainly to the NPs rather than copper itself. Thus another mechanism not related with Cu,Zn-SOD and CAT seems to be involved.