Table 2. Main Findings of the Studies on Histopathology Changes in Different Tissues of the Brain, Liver, and Kidneys of Wistar Rats at Different Doses of Small-Size GNPs (c. 20 nm).

organ	dose of gold nanoparticle	histological result
brain	25, 50, and 100 mg/kg	inflammatory cells and congestive vessel
	250 mg/kg	several outbreaks of necrosis highlighted by the glial cell space
liver	25 and 50 mg/kg	congestive vessel
	100 mg/kg	lymphocytic infiltration, inflammation, and congestive vessel
	250 mg/kg	congestive vessel, lymphocytic infiltration, and focal areas of necrosis
kidneys	25 mg/kg	congestive vessels
	50 mg/kg	lymphocytic infiltration and congestive vessels
	100 mg/kg	several congestive vessels
	250 mg/kg	tubular degeneration and necrotic state