Protective Effects Of Heparin On Lipopolysaccharide-induced Mitochondrial Damage And Endothelial Cell Apoptosis In Human Pulmonary Vascular Endothelial Cells

Objective: Mitochondria is an important part of the cell structure,with a variety of metabolic and signaling functions.mitochondrial dysfunction may be the central part of multiple organ dysfunction caused by sepsis.Therefore,protecting mitochondria from damage may be beneficial for the treatment of sepsis.Lipopolysaccharide(LPS),a key component in the pathogenesis of sepsis,can promote endothelial cell apoptosis,increase reactive oxygen species(ROS)production and induce mitochondrial dysfunction.Our previous studies showed that heparin has a protective effect on LPS-mediated endothelial inflammatory responses,but there is no studies have shown that the effect of heparin on the damage of endothelial mitochondria and endothelial cell apoptosis.Methods: 1.Dividing HPMECs into four groups: control,LPS,LPS+UFH and UFH.Injury was induced by co-incubation of LPS10ug/ml with human pulmonary microvascular endothelial cells.10U/ml unfractionated heparin was added to the heparin group by 2 hours earlier,and the control group was added the same amount of pbs and the cells were collected after 12 hours.JC-1 method for determinating the mitochondrial membrane potential level of the cells in each group.2.Dividing HPMECs into four groups: control,LPS,LPS+UFH and UFH.Injury was induced by co-incubating LPS10ug/ml with human pulmonary microvascular endothelial cells.10U/ml unfractionated heparin was added to the heparin-treated group by 2 hours earlier,and the control group was added the same amount of pbs,and the cells were collected after 24 hours,and the apoptosis of the cells were detected by Annexin V-FITC / PI.Results: 1.Making a patch against the control group(5.89±1.05,n=3),the ratio of red fluorescence-labeled cells to green fluorescence-labeled cells in LPS group was significantly lower than that in the control group(P<0.05),suggesting that the mitochondrial membrane potential of this group was lower than that of the control group.LPS caused mitochondrial membrane potential abnormalities;The ratio of red fluorescence-labeled cells to green fluorescence-labeled cells in UFH+LPS group(5.72±0.40,n = 3)was increased obviously than the LPS group(3.20±1.09,n = 3),P<0.05 indicated that the membrane potential of this group was obviously higher than that of LPS alone,and heparin antagonized the decrease of mitochondrial membrane potential induced by LPS.2.The rate of early apoptosis in the LPS group(14.1±3.92,n=3)was obviously higher than that in the control group(7.01±1.02,n=3),P<0.05,suggesting that LPS could induce endothelial cell apoptosis;The early apoptosis rate in the LPS+heparin group(7.54 ±1.64,n=3)was obviously lower than that in LPS alone(14.1±3.92,n=3),P<0.05,suggesting that heparin can relieve LPS-induced apoptosis.