['Preeclampsia (PE) is one of the most common and dangerous complications during pregnancy and is characterized by high blood pressure and significant amounts of protein in the urine. Vascular endothelial cell dysfunction is the major pathology in PE. This study was designed to assay the effects of tanshinone II-A (TII-A) on human umbilical vein endothelial cell (HUVEC) injury after incubation with serum from PE patients and to determine the underlying mechanism.', 'After treating HUVECs with different TII-A concentrations, cell viability, apoptosis and CD40/CD40 ligand (CD40L) mRNA and protein expression levels were measured.', 'Incubation of HUVECs with serum from PE patients induced morphological alterations, caused decreased cell viability and increased the rate of apoptosis. However, TII-A (5-40 μg/ml) significantly reversed these injuries. Importantly, preapplication of TII-A attenuated PE sera-induced expression of CD40 and CD40L mRNA and protein.'] Is tanshinone II-A protective against human umbilical vein endothelial cell injury after exposure to serum from preeclampsia patients?