title: [Protective effects of autophagy against oxidized LDL-induced injury in endothelial cells].
abstract: OBJECTIVE
  To investigate the role of autophagy in oxidized low density lipoprotein (ox-LDL) induced injury of human umbilical vein endothelial cells (HUVEC).
  
  
  METHODS
  The cultured HUVECs were randomly divided into four groups of control, ox-LDL, ox-LDL + rapamycin and ox + 3-methyladenine (3-MA). The cells were used to detect the ratio of LC3-II/LC3-I by Western blot while the proliferation and apoptosis of cells measured by MTT and flow cytometry. The lactate dehydrogenase (LDH) activity and endothelin-1 (ET-1) content in the supernatant were detected with enzyme linked immunosorbent assay.
  
  
  RESULTS
  The Ox-LDL treatment up-regulated the ratio of LC3-II/LC3-I in HUVEC (P < 0.01). It increased the activity of LDH (P < 0.01)and content of ET-1 (P < 0.05) in the supernatant. Also it induced the proliferation (P = 0.028) and apoptosis (P < 0.05) of cells. The autophagic inducer rapamycin increased the up-regulation of autophagic level induced by ox-LDL, decreased the activity of LDH and content of ET-1 (P < 0.05) and inhibited the ox-LDL-induced proliferation of cells. Conversely, the autophagic inhibitor 3-MA decreased the elevation of LC3-II/LC3-I induced by ox-LDL (P < 0.01) and increased the cell apoptosis and death.
  
  
  CONCLUSIONS
  Ox-LDL exposure can increase the secretion of LDH and ET-1 and induce the proliferation and apoptosis of cells so as to cause a harmful effect in the survival of HUVEC. The injury may be reduced by rapamycin, an autophagic inducer, and elevated by the autophagic inhibitor 3-MA.
authors.affiliation: Department of Neurology, Second Affiliated Hospital of Soochow University, Suzhou 215004, China.
authors.forename: Yan-lin
authors.initials: YL
authors.lastname: Zhang
authors.forename: Yong-jun
authors.initials: YJ
authors.lastname: Cao
authors.forename: Shou-jiang
authors.initials: SJ
authors.lastname: You
authors.forename: Rui-xia
authors.initials: RX
authors.lastname: Li
authors.forename: Hui-hui
authors.initials: HH
authors.lastname: Liu
authors.forename: Chun-feng
authors.initials: CF
authors.lastname: Liu
mesh_terms: D017209:Apoptosis; D001343:Autophagy; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology*; D019332:Endothelin-1 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008077:Lipoproteins, LDL / Q000009:adverse effects*; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism
chemical_list: D019332:Endothelin-1; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein