Time-course effects of intravenously administrated silica nanoparticles on blood coagulation and endothelial function...

Among the most used inorganic nanomaterials, silica nanoparticles (NPs) have been considered as either drug carriers or contrast agents. Though the distribution of silica NPs via the circulation appears highly probable, to date, there are few studies investigating the vascular effects of silica NPs in vivo. This study was designed specifically to investigate whether silica NPs with intravenous injection could lead to blood coagulation disorder and endothelium dysfunction in vivo. The time-course effect of silica NPs on blood coagulation, oxidative stress and the expression of soluble E-selectin (sE-selectin) and tissue factor (TF) in the plasma of Sprague Dawley (SD) rats were presented. Our data showed that a shortened prothrombin time (PT) was observed on 1 day after exposure to silica NPs, while activated partial thromboplastin time (APTT) was not affected at any time-points. After the post-injection respectively, the levels of fibrinogen (Fbg) were increased by silica NPs from 1 day to 3 days, and returned to normal value on the 7th day. Meanwhile, a sustained increase in the levels of TF and sE-selectin was elicited by silica NPs during 7 days after the injection. In addition, after 7 days of intravenously injection of silica NPs, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) in the plasma of SD rats were decreased significantly, whereas the level of malondialdehyde (MDA) was not changed obviously. In conclusion, intravenously administration of silica NPs could shorten PT but not APTT increase TF and sE-selectin release and reduce GSH-px and SOD activity in the plasma of SD rats, indicating exposure to silica NPs could early activate coagulation cascade via the extrinsic pathway, and may be dependent on endothelium dysfunction and oxidative stress.