Circadian rhythm of malondialdehyde formation in healthy subjects

Abstract

Objective:Malondialdehyde (MDA) is a common biologic marker of oxidative stress used in psychiatric research. Data regarding MDA levels in healthy subjects are controversial. One factor affecting MDA levels may stem from the existence of a circadian rhythm of MDA formation. The objective of this study consists of investigating whether MDA formation has a circadian rhythm of formation in healthy human subjects.Methods:The sample was comprised by 9 healthy male subjects. None of them had a history of medical or neurological disease and routine laboratory parameters were normal. The study was carried out in accordance with the Helsinki Declaration and all subjects gave written informed consent before their inclusion. Blood samples were extracted at 12:00 and 2:00 in December 2004. The same routine was followed during the two experimental sessions. Serum MDA was determined by the thiobarbituric acid reactive substance (TBARS) according to the method of Ohkaba et al (1979).Results:The sample was comprised by 9 male healthy subjects (age 33.0±11.7). There were significant differences in MDA levels between 12:00 and 2:00 (2.33±1.01 vs. 1.58±0.48, p<0.015).Conclusions:MDA has a circadian rhythm of formation with higher levels at 12:00 than 2:00. This variation in circadian MDA levels of formation should be accounted when researching in this field.