Effect of circadian rhythm disturbances on peroxisomal lipid metabolism

Aim: Circadian rhythm disorders are common in modern life conditions and they are involved in pathogenesis of cancer, metabolic syndrome, diabetes and other chronic diseases. Lipidomic studies revealed that circadian rhythm disorders increased some plasmalogen levels, a peroxisomal metabolite. Therefore; in this study, we aimed to determine whether circadian rhythm disorders affect peroxisomal lipid metabolism. Material and Metod: Constant light exposure, calorie restriction and time-restricted feeding were applied for two weeks in order to alter circadian rhythm in rats. An another group was assigned to food supplementation with phenofibrate to evaluate and to compare peroxisomal activation. Plasmalogens were analyzed by GC method in the erythrocyte membrane; very long chain fatty acids (C22, C24, C26), pristanic acid and phytic acid levels analyzed by GC-MS method in rat plasma. Peroxisomal activation was evaluated by immunohistochemical methods in liver. Results: Plasmalogen levels were significantly lower in the erythrocyte membrane of the FF, SA and KK groups. While some of PUFAs in the membrane phospholipids decreased whereas palmitic acid levels were increased. While peroxisomal lipid metabolism was active in FF, it was inactive in KK group. In groups with circadian arrhythmia, there was an increase in catalase immunreactivity along with hydropic changes in the liver. Conclusion: The various conditions that disrupt the circadian rhythm have created similar effect on erythrocyte membrane while caused different effects on peroxisomes. Therefore we conclude that the evaluation of erythrocyte membrane phospholipid composition in circadian rhythm disorders can also be a valuable tool in the diagnosis and treatment of these disorders.