Potential role of pioglitazone, caffeic acid and their combination against fatigue syndrome-induced behavioural, biochemical and mitochondrial alterations in mice

Chronic fatigue is an illness characterised by persistent and relapsing fatigue, often accompanied by numerous neuropsychiatric problems, such as anxiety and depression. The aetiology of chronic fatigue remains unclear so far. However, recent studies suggested the involvement of oxidative stress in this chronic debilitating disease. Alternatively, antioxidants have also been reported to have beneficial effect against chronic fatigue-like conditions. Therefore, present study has been designed to explore the potential role of pioglitazone, caffeic acid and their combination against chronic fatigue-like condition in mice. In the experimental protocol, the mice were put on the running wheel apparatus for 6 min test session daily for 21 days which produced fatigue-like condition. The locomotor activity and anxiety levels were measured on 0, 8th, 15th and 22nd days. The brains were isolated on 22nd day immediately after the behavioural assessments, oxidative damage and mitochondrial enzyme complexes were then estimated subsequently. Three weeks pioglitazone (5 and 10 mg/kg) and caffeic acid (5 and 10 mg/kg) pretreatment significantly attenuated the chronic fatigue-like condition (restored running wheel activity, locomotor activity and reduced anxiety-like behaviour) as compared to that in control (chronic fatigue) animals. Further, pioglitazone (5 and 10 mg/kg) and caffeic acid (5 and 10 mg/kg) drug treatments for 3 weeks significantly attenuated oxidative damage (decreased lipid peroxidation, nitrite concentration, restored reduction in glutathione and catalase levels), altered mitochondrial enzymes complex (I, II and IV) activities and mitochondrial redox activity (MTT assay) when compared with control. Further, combination of lower dose of pioglitazone (5 mg/kg) and caffeic acid (5 mg/kg) showed significant synergism in their protective effect which was significant as compared to their effect per se. The present study highlights the potential role of pioglitazone, caffeic acid and their combination in the pathophysiology of chronic fatigue-like condition in mice.