Mechanism of Microvascular Endothelial Cells Protected by Pulsatillae Decoction Activated Neutrophils to Kill Bacteria

Abstract Neutrophils play critical a role in bacterial infection and tumor immunity. The migration of neutrophils across microvascular endothelial cells has been a focus of increased interest within the past decade. A traditional Chinese herbal formula, Pulsatillae Decoction (PD), has the effects of improving the permeability of MVECs, inhibiting apoptosis and enhancing cell activity. But there are very few studies linking the three, and the effect of PD on the bactericidal function of PMNs transendothelial migration is unclear. To investigate the protective effect of PD on the damage of Rat microvascular endothelial cells (RIMVECs) induced by LPS and it’s mechanism of activating neutrophils (PMNs) to kill bacteria by protecting RIMVECs, we established a model of LPS-induced RIMVECs injury and to evaluate the protection of PD against LPS-induced RIMVECs injury. We observed that LPS-injured RIMVECs inhibited the extracellular and intracellular bactericidal activity of transendothelial neutrophils, PD-protected RIMVECs promoted the extracellular and intracellular killing activity of transendothelial neutrophils and significantly increased NE and CG concentration in transendothelial neutrophils. In addition, SWATH/DIA proteome results showed that 11 consensus proteins were down-regulated in the model group and up-regulated in the treatment group, 23 consensus proteins were up-regulated in the model group and down-regulated in the treatment group. PD was likely to protect RIMVECs and activate the sterilization of PMNs by regulating these differential proteins.