Possible role of oxidative stress and immunological activation in mouse model of chronic fatigue syndrome and its attenuation by olive extract.

Various putative theories involved in the development of chronic fatigue syndrome revolve around the role of stress, infection and oxidative stress. Scientific evidence highlighting the protective role of nutritional supplements in chronic fatigue syndrome is lacking. Based on these assumptions, the present study was designed to evaluate the effect of olive extract in a mouse model of immunologically-induced fatigue, wherein purified lipopolysaccharide (LPS) and Brucella abortus (BA) antigen were used as immunogens. The assessment of chronic fatigue syndrome was based on immobility period during chronic water-immersion stress test for 10 min daily. The stress-induced hyperalgesia was measured by tail withdrawal latency. Mice challenged with LPS or BA for 19 days showed significant increase in the immobility time, hyperalgesia and oxidative stress on the 19th day. Serum tumor necrosis factor-alpha (TNF-α) levels were also markedly increased with LPS or BA challenge. Concurrent treatment with olive extract resulted in a significant decrease in the immobility time as well as hyperalgesia. There was significant attenuation of oxidative stress as well as serum TNF-α levels. The results of the present study strongly indicate the role of oxidative stress and immunological activation in the pathophysiology of chronic fatigue syndrome and highlight the valuable role of olive extract in combating chronic fatigue syndrome.