Environmental
polychlorinated biphenyls (
PCBs) are frequently bound onto nanoparticles (NPs). However, the toxicity and health effects of
PCBs assembled onto nanoparticles are unknown. The aim of this study was to study the hypothesis that binding
PCBs to
silica NPs potentiates PCB-induced cerebrovascular toxicity and brain damage in an experimental
stroke model. Mice (C57BL/6, males, 12-week-old) were exposed to
PCB153 bound to NPs (PCB153-NPs),
PCB153, or vehicle.
PCB153 was administered in the amount of 5 ng/g
body weight. A group of treated animals was subjected to a 40 min
ischemia, followed by a 24 h reperfusion. The blood-brain barrier (BBB) permeability,
brain infarct volume, expression of tight junction (TJ)
proteins, and inflammatory mediators were assessed. As compared to controls, a 24 h exposure to PCB153-NPs injected into cerebral vasculature resulted in significant elevation of the BBB permeability, disruption of TJ
protein expression, increased proinflammatory responses, and enhanced monocyte transmigration in mouse brain capillaries. Importantly, exposure to PCB153-NPs increased stroke volume and potentiated brain damage in mice subjected to
ischemia/reperfusion. A long-term (30 days) oral exposure to PCB153-NPs resulted in a higher
PCB153 content in the abdominal adipose tissue and amplified adhesion of leukocytes to the brain endothelium as compared to treatment with
PCB153 alone. This study provides the first evidence that binding to NPs increases cerebrovascular toxicity of environmental toxicants, such as
PCB153.