Author(s): Sener A, Ozsavci D, BingolOzakpinar O, Cevik O, YanikkayaDemirel G,
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Abstract Low-density lipoprotein (LDL) modifications and platelet activation are major risk factors for cardiovascular diseases. When platelets are exposed to oxidative stress, they become activated. Oxidized LDL (ox-LDL) and metal-catalysed oxidation systems such as Fe3+/ascorbic acid increase free radical production. We wanted to verify whether melatonin has a protective effect against oxidative modifications and phosphatidylserine externalization in platelets induced by ox-LDL and Fe3+/ascorbic acid. For in vitro effects of melatonin on platelets, ADP-activated platelets were incubated with ox-LDL or Fe3+/ascorbic acid for 1 h at 37 degrees C with or without melatonin. Then platelet malondialdehyde, protein carbonyl and glutathione levels were measured. Platelet phosphatidylserine exposure was measured with annexin-V using flow cytometry. Malondialdehyde, protein carbonyl and phosphatidylserine levels of platelets treated with Fe3+/ascorbic acid significantly increased compared to the control group. Glutathione contents of Fe3+/ascorbic acid-treated platelets significantly decreased. Melatonin pre-treatment of Fe3+/ascorbic acid-treated platelets caused a mar ked reduction in malondialdehyde and phosphatidylserine levels and a marked increase in glutathione levels. Melatonin also caused non-significant reduction in protein carbonyl contents of Fe3+/ascorbic acid-treated platelets. Malondialdehyde, protein carbonyl and phosphatidylserine levels of platelets treated with ox-LDL also significantly increased compared to the control group. Platelet glutathione levels non-significantly decreased with ox-LDL. With addition of melatonin, malondialdehyde, protein carbonyl and phosphatidylserine levels of platelets treated with ox-LDL significantly decreased. These data suggest that melatonin may protect platelets from iron overload-induced and ox-LDL-induced oxidative modifications and also from the triggering signals of apoptosis activation, possibly due to its scavenger effect on toxic free radicals.
This article was published in Folia Biol (Praha)
and referenced in Journal of Diabetes & Metabolism