[Comparative evaluation of the cytotoxic effect of hydrogen peroxide and tumor necrosis factor alpha on nonischemic and ischemic endothelial cells].
We studied cytotoxic effects (CTE) induced in confluent cultures of human umbilical vein endothelial cells (HUVEC) by initiators of free-radical reactions (FRR): H2O2 (10(-6)-10(-9) M), recombinant human tumor necrosis factor-[symbol; see text] (TNF-alpha, 0.05-100 ng/ml), and a combination of TNF-alpha with low-density lipoproteins (LDL, 100 microgram/ml). HUVEC were incubated with these substances for 6 or 24 h in parallel tests performed under aerobic (CO2-incubator) and ischemic conditions (a mixture of 95% N2 + 5% CO2 in RPMI-1640 medium containing no substrate additives, growth factor or protein). HUVEC viability was determined by counting cells adherent to the bottom of wells after 24 h of reincubation under aerobic conditions in the growth medium (Plating Efficiency Index). The data showed that: 1) CTE of these compounds were dose-dependent (H2O2 and TNF-alpha) and time-dependent (TNF-alpha); 2) CTE of FRR initiators and CTE of ischemia were synergistic, that is, their combination produced a greater decrease HUVEC viability than any substance examined or ischemia alone; 3) CTE of TNF-alpha observed in experiments in substrate-deficient, protein-free medium was considerably stronger than in the growth medium; 4) a combination of TNF-a and LDL caused a stronger CTE on HUVEC than either factor alone, and this synergism was more pronounced during incubation under ischemic conditions. Thus, the data indicate that FRR initiators and TNF-alpha + LDL particularly increase the severity of ischemic injuries of EC and therefore they can be factors which in hypercholesterolemic patiens predispose vascular wall to atherosclerosis.
Institute of Biomedical Chemistry RAMS. Moscow.
M V
MV
Bilenko
V G
VG
Ladygina
S V
SV
Fedosova
D002478:Cells, Cultured; D003470:Culture Media; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000473:pathology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007511:Ischemia / Q000473:pathology*; D008077:Lipoproteins, LDL / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D003470:Culture Media; D008077:Lipoproteins, LDL; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D006861:Hydrogen Peroxide