Oxidized low-density lipoproteins induce apoptosis in aortic and endocardial endothelial cells
Abstract
AIM: To examine whether oxidized low-density lipoproteins (ox-LDL) might induce
apoptosis in bovine aortic and endocardial endothelial cells (BAEC and BEEC).
METHODS: Low-density lipoproteins (LDL) were isolated from healthy human plasma
by ultracentrifugation and oxidized by CuSO4 10 mumol.L-1. BAEC and BEEC were
incubated in a medium containing ox-LDL, LDL, or phosphate-buffer solution (PBS)
as control. DNA fragmentation was visualized by agarose gel electrophoresis and
determined quantitatively using Hoechst-33258 fluorochrome.
RESULTS: Ox-LDL, not LDL, elicited typical apoptotic changes and DNA
fragmentation in BAEC and BEEC. In BAEC, dextran sulfate, and cicloheximide (Cic)
exhibited no effect on DNA fragmentation induced by ox-LDL. Butylated
hydroxytoluene (BHT) 20 mumol.L-1 completely inhibited Cu(2+)-mediated oxidation
of LDL as well as the apoptosis-inducing effect of Cu(2+)-exposed LDL.
Lysophosphatidylcholine (LPC) did not elicit DNA fragmentation in BAEC and in
BEEC. DNA fragmentation induced by ox-LDL in BAEC and in BEEC was blocked by
chelating the calcium of the culture medium by egtazic acid.
CONCLUSION: Ox-LDL induces apoptosis in BAEC and BEEC without involving the LPC.
Keywords:
apoptosis in bovine aortic and endocardial endothelial cells (BAEC and BEEC).
METHODS: Low-density lipoproteins (LDL) were isolated from healthy human plasma
by ultracentrifugation and oxidized by CuSO4 10 mumol.L-1. BAEC and BEEC were
incubated in a medium containing ox-LDL, LDL, or phosphate-buffer solution (PBS)
as control. DNA fragmentation was visualized by agarose gel electrophoresis and
determined quantitatively using Hoechst-33258 fluorochrome.
RESULTS: Ox-LDL, not LDL, elicited typical apoptotic changes and DNA
fragmentation in BAEC and BEEC. In BAEC, dextran sulfate, and cicloheximide (Cic)
exhibited no effect on DNA fragmentation induced by ox-LDL. Butylated
hydroxytoluene (BHT) 20 mumol.L-1 completely inhibited Cu(2+)-mediated oxidation
of LDL as well as the apoptosis-inducing effect of Cu(2+)-exposed LDL.
Lysophosphatidylcholine (LPC) did not elicit DNA fragmentation in BAEC and in
BEEC. DNA fragmentation induced by ox-LDL in BAEC and in BEEC was blocked by
chelating the calcium of the culture medium by egtazic acid.
CONCLUSION: Ox-LDL induces apoptosis in BAEC and BEEC without involving the LPC.