| Objective Angiotensin ? (Angiotensin ?, Ang ?) can participate in the development of many cardiovascular diseases by binding to certain receptors. As the first barrier of artery,the endothelial cells are more prone to injury and associated with the occurrence of diseases such as atherosclerosis, myocardial infarction or heart failure. The mitochondria of endothelial cells have the ability of energy storage and maintain the balance of ROS and NO as well as the equilibrium of calcium inside the cells. Thus the study chooses Ang II injuried human umbilical vein endothelial cells (HUVECs) to investigate the bioenergetical role of mitochondrial respiratory chain dysfunction.Methods HUVECs were treated with different concentrations of Ang ?. The flow cytometry technique was used to detect reactive oxygen species, mitochondrial membrane potential, cell cycle and cell apoptosis of HUVECs. The XF-96 extracellular flux analyzer was used to measure basic breath function, the maximum respiratory rate, the level of ATP, proton leak and respiratory ctrl ratios of HUVECs. The UV spectrophotometer was used to determine the activities of mitochondrial complex ?. The changes of protein level of ND1 and ND2 were measured by Western Blot.Results1. The rate of apoptosis cells were increased with the degree of Ang ? concentration (from 10-8 mol/L to 10-5 mol/L). The apoptosis indexes of cells were 24.52 ± 2.37, 27.91 ± 1.57,41.13 ± 1.06 and 66.32 ± 1.34 compared to ctrl group (16.37 ± 1.21). The production of ROS in HUVECs increased markedly from 88.31 ± 6.04 to 40.53 ± 4.10, n=3(P<0.001). The cell proliferation was significantly increased from 22.64 ± 5.21 to 35.56 ± 2.69 at the concentration of Ang ? 10-9mol/L(n=5, P<0.05). The in Ang ? group was significantly lower compared to ctrl group. (34.62 ± 3.52 vs.26.79 ± 2.43, n=3>, P<0.05).2. The basic respiration of HUVECs was first increased and then decreased with the increased concentration of Ang II. Compared to the ctrl group, the basic respiration of HUVECs was decreased significantly at the concentration of 10-5 mol/L Ang II. Likewise, the production of ATP was first increased and then decreased, the respiratory reserve was markedly decreased with higher concentration fo Angll ( Ang II 10-6 mol/L vs. Ctrl:12.3 ± 1.8 vs.22.3 ± 1.5, n=5, P<0.01), whereas it was increased at the Ang ? concentration of 10-7 mol/L and 10-8 mol/L. (Ang ? 10-8 mol/L:28.2 ± 1.1 vs. Ctrl:22.3 ± 1.5, n=5, P<0.01; Ang ? 10-7 mol/L:27.5 ± 2.3 vs. Ctrl:22.3 ± 1.5, n=5,P<0.01)3. The activity of mitochondrial respiratory chain complex I was 5.6 ± 2.4 U/ml compared to 4.2 ± 2.1 U/ml of ctrl group(n=3, P<0.05)4. Compared to ctrl group,the protein expression of ND1 and ND2 were significantly decreased with the increasing concentration of AngII.(P< 0.05)Conclusion1. With the increasing of Ang ? concentration, the apoptosis of HUVECs became serious correspondingly.2. High concentrations of Ang II destroyed the normal function of mitochondrial respiratory chain, weakened the normal breathing of mitochondrial, disabled ATP synthesis, and bated maximal respiration capacity.3. Ang ? can not affect the normal function of mitochondria in short time, which suggesting that mitochondrial has spare capacity for responding with appropriate stimuli, and can increase ATP production in a certain range, and maintain the normal function of respiratory chain.4. Ang ? may cause the activity decrease of mitochondrial respiratory chain complex ?, and expression decrease of ND1 and ND2. |
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