Quercetin mitigates pro-inflammatory effects of polyvinylpyrrolidone-coated silver nanoparticles on human intestinal...

Extended oral intake of silver nanoparticles (AgNP) may result in significant exposure of intestinal cells, which could trigger intestinal inflammation, an effect that requires deep comprehension and the development of mitigation measures. This study aimed to investigate the potential pro-inflammatory effects of polyvinylpyrrolidone (PVP)-coated AgNP with two different sizes (5 and 50 nm) on human intestinal epithelial C2BBe1 cells, as well as the potential mitigation effects of quercetin, a flavonoid with acknowledged antioxidant and anti-inflammatory potential. The pro-inflammatory effects of PVP-AgNP on several proteins related to the intestinal inflammatory response, as well as on ^●NO production and cytokine production, were investigated. PVP-AgNP exposure caused cellular stress and damage, as evidenced by a reduction in cellular metabolic activity, ultrastructural changes, and loss of viability. The present study also found that 5 nm PVP-AgNP triggered inflammation through the p65-induced NF-κB pathway and reduced p-Nrf2 expression, while 50 nm PVP-AgNP activated the IκBα-induced NF-κB pathway and elevated COX-2 levels. Both sizes induced an increase of PGE₂ levels and IL-8 production, with only 5 nm PVP-AgNP increasing IL-6. The harmful effects of PVP-AgNP were effectively mitigated by quercetin, which highlights the potential of this flavonoid to modulate the respective potential damage at the intestinal level.