The Injury Mechanism In Human Umbilical Vein Endothelialcells Under Uremic Serum Environment And The Protective Effects Of L-carnitine

Objective: Cardiovascular complications are the main cause of death in uremic patients. Uremic angiopathy has been regarded as an accelerated form atherosclerosis. Previous study showed oxidative stress, microinflammation state, and endothelial dysfunction as burden of atherosclerosis is undorbtedly increased in renal failure. However, the mechanism leading to vessel wall injury under uremic serum envirnment is still unknown. Therefore, this study sought to investigate the injury echanism in human umbilicalvin endothelial cells under uremic serum environment and the effect of levocarnitione on endothelial dysfunction , microinflammation and oxidative.Methods: 1. We made a uremic environment invitro model using serum from 15 patients with chronic renal failure undergoing hemodialysis just before the dialysis session. Any three patients'serum were mixed together. At last, cell were incubated with 5 group of pooled sera. We also clollected serum from 15 healthy donors. None of the patients or healthy donors had experienced infections or other diseases known to activate the immune system in the 8 weeks preceding blood withdrawal . 2. The observation of the injury echanism in HUVEC: Cultured HUVEC were incubated with uremic serum( 2.5%, 5%, 10%, 15%) or healthy serum ( 2.5%, 5%, 10%, 15%), compared with 1% new born Calf Serum. 3. Effect of levocarnitione on endothelial cell: The uremic serum with or without L-CN(25μM, 250μM, 1000μM, 2500μM) was used in culture medium to stimulate the HUVEC compared with control group. 4. Methods: Cell viability was assessed by measuring their ability to metabolize the MTT salt; Semi-quantitative reverse transcription polymerase chain reaction(RT-PCR) were applied to detect the expression of IL-6, the protein level of IL-6 in HUVEC was detected by ELISA. The cells were marked with oxidation-susceptible fluroscent probe 2,7-dichorofluoresin diacetate(DCFH) and were assayed by Spectrofluorophotometric detector. NO and MDA were detected by spectrophotometerResults: 1. Incubation with uremic serum reduced the proliferation of cells and was paralleled by a gradual loss of cell viability .At the same time NO in HUVEC was reduced significangtly, and MDA was increased significantly compared with health group. The change was dose-dependently compared with normal group and could been improved by L-CN. 2. The increased expression of IL-6 and ROS was found in uremic serum groups compared with normal group, however, the effects of uremic serum environment on HUVEC could be ameliorated by antioxidant L-CN(250μM～2500μM) with a dose-dependent manner.Conclusion: Uremic serum lead to endothelial dysfunction, multproduction of ROS, and expression of IL-6 . L-CN inhibits Uremic serum environment-induced ROS and IL-6 in HUVEC, which suggests that L-CN may exert antiatherogenic effects partly by influencing the oxidative stress and microinflammation in HUVEC which plays an important role in atherosclerosis.