Effect of naked and PEG-coated gold nanoparticles on histopathology and cytokines expression in rat liver and kidneys.

Aim: To compare the effects of 5- and 50-nm naked and PEG-coated gold nanoparticles (AuNP) on proinflammatory cytokines (IL-1β, IL-6, TNF-α) expression and histopathological changes in liver and kidneys of rats. Materials & methods: Rats were injected with different nanoparticles and sacrificed after 24 h. Results: Both 5- and 50-nm AuNPs, and 50-nm PEG-AuNPs caused granular clumping of cytoplasm, edema and hydropic dystrophy in hepatic cells. Naked AuNPs of both sizes caused mild shrinkage, whereas 50-nm PEG-AuNPs enlarged the Bowman's space and capsule. Larger nanoparticles produced more profound mRNA expression of cytokines in both the organs. Conclusion: These findings suggest the roles of particle size and coating on immunological response and histopathological changes.