Biological Response Of Polymerized Porcine Hemoglobin On Vascular Endothelial

Polymerized porcine hemoglobin (pPolyHb) is a new type of Hemoglobin-based oxygen carriers (HBOCs), which are synthesized from chemically modified hemoglobin. HBOCs are developed as a kind of red blood cell (RBC) substitute that can partially replace the function of RBC. pPolyHb can be used in the treatment of trauma such as hemorrhagic shock and intraoperative blood loss and severe anemia. In previous studys, HBOCs were found to cause vasoconstriction, induced by scavenging the NO generated by endothelial cell, which would increase arteries blood pressure and pulmonary vascular resistance. Vascular endothelium plays an important role in adjusting vascular tension and steady state. pPolyHb has good capacity of oxygen carrying and releasing, and the free hemoglobin in pPolyHb could be reduced as low as possible during production. Therefore, pPolyHb may reduce the effect of vasoconstriction to some extent. The effects of pPolyHb on vascular endothelial cells were evaluated via animal model such as toplod and hemorrhagic shock models and cell culture in vitro.In vivo study, topload model and hemorrhagic shock model were established. The structure of mesentieric endothelial cells was observed via microscope and transmission electron microscope, and the level of ET-1, sICAM-1, vWF was measured to examine the effect of pPolyHb on endothelial cells. In topload model, the results showed that the structure of mesentieric endothelial cells was not affected. There were no significant changes between the levels of ET-1, sICAM-1 and vWF of pPolyHb group and HES group compared to control. Hemorrhagic shock resuscitation model can cause vascular endothelium dysfunction, but infusion of 2g/kg pPolyHb plus two times physiological saline can relieve the endothelial injury caused by hypoxia and restoration compared with HES and saline group.In vitro, HUVECs was used as target cells and ischemia recovery model was set up to simulate hemorrhagic shock resuscitation of animal. Cells’ survival rate and apoptosis rate were detected by MTT assay and flow cytometer. mRNA and protein expression level of NOS3, HO-1, ET-1 and sICAM-1 of HUVECs’were analyzed through RT-PCR and Western blot assay to investigate the effect of pPolyHb on endothelial cells in vitro. The result illustrated that there were no significant effect on endothelial cells’ survival and NO synthesis when pPolyHb administrated. pPolyHb could alleviate some necrosis and apoptosis caused by ischemia hypoxia. In addition, pPolyHb will stimulate HUVECs to produce HO-1 and sICAM-1 to enhance the cellular antioxidant and anti-inflammatory function.