Oxidized low-density lipoproteins induce apoptosis in vascular smooth muscle cells.
OBJECTIVE
To examine whether oxidized low density lipoproteins (ox-LDL) could induce apoptosis in rabbit aortic smooth muscle cells (VSMC).


METHODS
Low density lipoproteins (n-LDL) were isolated from healthy human plasma by gradient ultracentrifugation and oxidized by CuSO4 10 mumol.L-1. VSMC were exposed to ox-LDL, n-LDL, or phosphate-buffer solution (PBS) as control. Morphological changes were observed under fluorescene microscope after Hoechst 33258 staining. Extracted DNA was electrophoresized on agarose gel.


RESULTS
Incubation of VSMC with ox-LDL 300 mg.L-1, not n-LDL, for 24 h induced morphological apoptosis changes (chromatin condensation, nucleus fragmentation) and DNA fragmentation, which was furthered with the incubation time up to 48 h or at a concentration of 400 mg.L-1. Dextran sulfate, a scavenger receptor blocker and butylated hydroxytoluene (BHT), an antioxidant, exhibited no effect on DNA fragmentation. Lysophosphatidylcholine (LPC) at a concentration up to 125 mumol.L-1 (equivalent to ox-LDL 300 mg.L-1) did not elicit DNA fragmentation.


CONCLUSIONS
Ox-LDL induced apoptosis in VSMC without involving oxygen free radicals and LPC.
Liu
W L
WL
Laboratory of Molecular Pharmacology, Hu-nan Medical University, Changsha, China.
Guo
X
X
Guo
Z G
ZG
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology; D017209:Apoptosis / Q000187:drug effects*; D053938:DNA Fragmentation; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D010084:Oxidation-Reduction; D011817:Rabbits
D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein