Inclusion Criteria:  Ability to understand and willingness to sign an informed consent form Elective lumbar spinal surgery that will take at least 120 minutes, American Society of Anesthesiologists (ASA) physical status I and II  Exclusion Criteria:  Patients with ASA physical status III or IV disease Chronic systemic disease (diabetes mellitus,chronic pulmonary disorders, chronic kidney and liver disorders) Smoking or alcohol consumption Recently received radiation, chemotherapy Malignancy Patients who will receive blood transfusion during the operation Users of antioxidant supplements Patients who have received general anesthesia in the last three months Patients with known occupational exposures (operating room personnel, chemical plant worker