Arachidonic acid cytotoxicity in leukocytes: implications of oxidative stress and eicosanoid synthesis

Abstract

Arachidonic acid (AA)-induced cytotoxicity was evaluated in leukocytes: the human leukemia cell lines HL-60, Jurkat and Raji and in rat lymphocytes. Such cytotoxicity was dose- and time-dependent. At concentrations below 5 microM, AA was not toxic; at 10-400 microM, AA induced apoptosis and at concentrations beyond 400 microM, necrosis. The minimum exposure time to trigger cell death was of around 1 h, but the effect was increased by longer exposure times until 6-24 h. Apoptosis was morphologically characterized by a decrease in cell and nuclear volume, chromatin condensation and DNA fragmentation and the presence of lipid bodies, without changes in organelle integrity. Biochemically, AA-induced apoptosis was associated with internucleosomal fragmentation and caspase activation, evaluated by PARP cleavage and the use of a caspase inhibitor. Necrosis was characterized by increased cell volume, presence of loose chromatin, appearance of vacuoles, loss of membrane integrity and of the definition of organelles. The apoptotic effect of AA was studied as to oxidative-reductive imbalance and the participation of eicosanoids. Apoptotic AA treatment was accompanied by an increase in the quantity of thiobarbituric acid reactive substances (TBARS), low-level chemiluminescence and in the glutathione disulfide/reduced glutathione ratio, indicating oxidative stress. The addition of tocopherol, ascorbate, prostaglandin E2 and lipoxygenase inhibitors delayed cell death, whereas the inhibition of cyclooxygenase promoted AA-induced cell death. Cell treatment with AA was accompanied by increased cellular production of LTB4. AA, therefore, is cytotoxic at physiological and supraphysiological concentrations, causing apoptosis and necrosis. Cell treatment with apoptotic concentrations of AA involves oxidative stress and changes in eicosanoid biosynthesis.

Effect of bullfrog (Rana catesbeiana) oil administered by gavage on the fatty acid composition and oxidative stress of mouse liver

“…The influence of dietary lipids on liver FA composition has been demonstrated in experimental animal studies using different oils (1,14,15). In the present study, intragastric administration of bullfrog oil caused an increase in long-chain PUFA (20:4n-6, 20:5n-3, and 22:6n-3) and a decrease in SFA (14:0, 16:0, and 18:0) in the liver.…”

“…Several studies have shown the influence of dietary fat on fatty acid (FA) composition and oxidative stress in various tissues (1)(2)(3)(4)(5)(6)(7)(8).…”

“…The proportion of FA in the diet is of great physiological importance since it can modulate the composition of FA in cell membrane phospholipids (1,2). This is due to the competition among FA families for elongation and desaturation enzymes.…”

Arachidonic acid triggers an oxidative burst in leukocytes

“…The low final values were probably due to cell necrosis, as visualized under the microscope. We have found that concentrations above 10 µM are apoptotic to these cell lines and those beyond 200 µM begin to induce necrosis (4). The concentration of 200 µM AA was adopted for further studies to avoid the cell changes inherent to necrosis, when there is extensive activation of proteases, nucleases, esterases among other degrading enzymes, and pronounced changes in metabolism.…”

Induction of Apoptotic Cell Death in HL-60 Cells by Jacaranda Seed Oil Derived Fatty Acids

“…3 , and the electrophoresis data showed an induction of DNA fragmentation at the JFA and JA concentrations that induced cell death. In the case of arachidonic acid, it induces oxidative stress-related apoptotic cell death at physiological concentrations and induces necrotic cell death at supraphysiological concentrations 24 . These data suggest that JA Data are mean ± SE of 3 measurements.…”