Effect of LDL-Ox on RAW macrophage survival

GONZALEZ, M. C.; TOLEDO, J. D.; ARNAL N.; MARRA C.

Potrero de los Funes, San Luis

Congreso; 47th Reunión anual. Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Isolated LDL fraction from human plasmas was in vitro peroxidized with Cu++ (5 µM) for 4 h (low, L), 8 h (medium, M) and 24 h (high, H) , dialyzed overnight to wash-out the copper ions, and assayed for 24 h at a final concentration of 100 µM in cultures Raw 264.7 murine macrophages to study the effect of LDL-Ox receptor activation on cell survival pathways. Percentage of dead cells -evaluated by trypan dye exclusion- compared to control flaks incubated with native LDL fraction was increased in the L, M and H assays. Lactate-dehydrogenase leakage was only significantly increased in cells treated with H-LDL. Specific activities of mili- and µ-calpaines picked in cultures treated with L fraction and returned to control values under M or H treatments. Caspase-3 activity increased consistently from L to H assays. These changes were observed concomitantly with increased activities of glutathione-peroxidase, -transferase and –reductase, catalase and superoxidedismutase. Total glutathione and the ratio GSH/GSSG were progressively decreased by these treatments (L to H). Results indicated that survival of macrophages exposed to oxidized LDL depends on the degree of peroxidation of the lipoprotein suggesting that the mechanism of damage is associated to alterations of the enzymatic antioxidant system and it involves different intracellular protease systems.