Beneficial Effects of Melatonin on Oxidative Damage Observed During Whole Blood Storage

It is well known that oxidative stress rises during the storing period of whole blood and there has been a great interest to improve the quality of stored blood for longer periods. In the present study, we determine the effects of melatonin as an antioxidant on the whole blood indices stored under blood bank conditions. Human blood was collected by venipuncture into citrate-dextrose-phosphate (CDP) bags from healthy volunteers. Immediately after collection, blood was subdivided into two parts and exposed to either melatonin or control saline solutions. Several biochemical parameters were measured on the day of collection and at weekly intervals up to 3 weeks. Mean corpuscular and platelet volumes tended to increase during storing process and with melatonin, these indices remained near to physiologic levels. As expected, acidity, oxidative damage and osmotic fragility increased in stored blood. Interestingly addition of melatonin reduced acidity, oxidative damage by lowering malondialdehyde levels and by increasing superoxide dismutase activity, and osmotic fragility during storage without adversely affecting other biochemical parameters. pH was 6.68 +/- 0.04 in day 14 of control group while it was 7.00 +/- 0.03 in melatonin group. Malondialdehyde level was 1.223 +/- 0.05 in day 21 of control group while it was 0.723 +/- 0.04 in melatonin group (p< 0.05). Superoxide dismutase activity was significantly higher in melatonin group at days 14 and 21(151.3 +/- 12.2 and 82.8 +/- 9.2) compared to saline (111.8 +/- 6.5 and 44.8 +/- 3.0) (p< 0.05). Through these results, we could confirm a central role for oxidative stress in the mechanism of the most evident blood storage lesions and melatonin seems to exhibit beneficial effects on these lesions.