Objective To explore the protective effect of mild hypothermia against the injury of vascular endothelial cells caused by polystyrene microplastics (PS-MPs).

Methods Human umbilical vein endothelial cells (HUVECs) were routinely cultured in DMEM medium containing 10% fetal bovine serum. HUVECs were exposed to PS-MPs and treated with mild hypothermia. The experimental groups were as follows: control group, PS-MPs exposure group, 33 ℃ mild hypothermia treatment group, and PS-MPs+33 ℃ mild hypothermia treatment group. The cell counting kit-8 assay was used to detect the cell survival rate, and flow cytometry was used to measure reactive oxygen species (ROS) level. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were measured by corresponding kits. Real-time polymerase chain reaction and Western blot were used to determine mRNA and protein expression levels of apoptotic genes of Bax and Bcl-2.

Results The ROS and MDA levels and Bax protein expression of HUVECs were significantly increased after exposure to PS-MPs (P < 0.05). Compared with the PS-MPs exposure group, the mild hypothermia treatment groups had significantly decreased the levels of ROS and MDA and the mRNA and protein expression levels of Bax (P < 0.05), significantly increased SOD levels (P < 0.05), and alleviated apoptosis of HUVECs.

Conclusion PS-MPs can cause oxidative stress and apoptosis of vascular endothelial cells, then damage vascular endothelial cells. Mild hypothermia plays a protective role by inhibiting oxidative damage and apoptosis.