Oxidized HDL are much less cytotoxic to lymphoblastoid cells than oxidized LDL

The possible effect of oxidized HDL was investigated on lymphoblastoid cells, in comparison to the cytotoxic effect of oxidized LDL. Oxidation of HDL was promoted by UV-C irradiation, or by copper ion (5 microM) or the combination of the two treatments. HDL extensively treated by UV-C for 20 h did not exhibit any cytotoxic effect on cultured lymphoblastoid cells even at a concentration of 500 micrograms apolipoprotein A-I/ml. In contrast to UV-treated (2 h) LDL, which were highly cytotoxic (already at a concentration of 100 micrograms apolipoprotein B/ml), HDL treated by copper or copper + UV were oxidized, as shown by TBARS formation and PUFA content decrease, but were slightly cytotoxic.