Nano-Mg(OH)2-induced proliferation inhibition and dysfunction of human umbilical vein vascular endothelial cells through caveolin-1-mediated endocytosis.

Nano-Mg(OH)2 is efficiently used in pollutant adsorption and removal due to its high adsorption capability, low-cost, and recyclability. A recent research from our group showed that Mg(OH)2 nanoflakes are not evidently internalized by cancer cells and are not cytotoxic. But the biocompatibility and potential toxicity of nano-Mg(OH)2 in a normal biological system are largely unclear. Nanoparticles could affect the function of endothelial cells, and endothelial dysfunction represents an early sign of lesion within the vasculature. Here, we applied the human umbilical vein vascular endothelial cells (HUVECs) as an in vitro model of the endothelium to study the cytotoxicity of nano-Mg(OH)2. Our results showed that nano-Mg(OH)2 at 200 μg/ml impaired proliferation and induced dysfunction of HUVECs, but did not result in cell necrosis and apoptosis. Transmission electron microscopy images and immunofluorescence results showed that the nano-Mg(OH)2 could enter HUVECs through caveolin-1-mediated endocytosis. Nano-Mg(OH)2 at high concentrations decreased the level of caveolin-1 and increased the activity of endothelial nitric oxide synthase (eNOS), thus leading to the production of excess nitric oxide (NO). In this work, we provide the cell damage concentrations of nano-Mg(OH)2 nanoparticles, and we propose a mechanism of injury induced by nano-Mg(OH)2 in HUVECs.