SOD1 and fibromyalgia: Case group, the participant with fibromyalgia syndrome; control group, participant without fibromyalgia syndrome; Cat, catalase enzyme; SOD, superoxide dismutase; GR, glutathione reductase; GPx, glutathione peroxidise; FIQR, fibromyalgia impact questionnaire-revised, p< 0.001*significance; MDA, malondialdehyde; NO, nitric oxide