Fig. 5.

Histopathological changes in liver and kidney of rats treated with copper nanoparticles (Cu NPs) and copper microparticles (Cu MPs) following 4 weeks-repeated oral dose. Liver from rats treated with Cu NPs at 400 mg/kg/day showed mononuclear cell infiltration (closed arrows), dilated sinusoid (open arrows), degenerated hepatocytes (vacuolation; open arrowheads), and binucleated hepatocytes (closed arrowheads). The rats treated Cu MPs at 400 mg/kg/day showed only dilated sinusoid. Kidneys from rats treated with Cu NPs showed dilated tubules (closed arrows), cell debris in tubules (closed arrowheads), pink- or purple-colored cast in tubules (open arrows), degenerated tubular cells (open arrowheads), and inflammatory cell infiltration (asterisks). The rats treated with Cu MPs did not show changes in kidney structure. Hematoxylin and eosin stain