Five weeks-old male Wistar rats (n=6 per group) were fed daily with 50 nm positively or negatively charged polystyrene nanoparticles (NPs) (12.5 mg/kg body weight) for two months. The analysis of their physical and biological parameters revealed a significant decrease in their heart rate and a substantial increase in their urine osmolality compared to control rats, suggesting that NPs exposure affects cardiovascular regulation and osmoregulation.
Immunofluorescence experiments performed with Iba-1 antibody to analyze microglial cells' morphology in the area postrema (AP), a blood-brain barrier-free cardiovascular center, revealed shorter branch length and fewer endpoints in rats exposed to NPs, suggesting that NPs exposure increased the reactivity of microglia in the AP.