The Correlation of COX-2 Expression in Human Polymorphonuclear Leukocytes/Macrophages (PMNL/MP) and Postoperative Pain

Inclusion Criteria: * The trial is approved by Tongji hospital's Ethics Committee, Tongji Medical College of Huazhong University of Science and Technology, and is registered through Clinical Trail. All patients give written informed consent * American Society of Anesthesiologists (ASA) physical status of I or II * 20 years to 55 years * Weight 50 \~ 70 kg, BMI 19 \~ 24 * Duration of operation time in the range of 2-4 hours * A normal leukocytes level before the operation * No alcohol or smoking abuse * Without major trauma, history of psychiatric disease and history of chronic pain * Patients agreement with the trial and having ability to complete the requirements of this study * Patients receiving intravenous patient controlled analgesia (PCA) Exclusion Criteria: * Allergy or contraindication to selective COX-2 inhibitors * Received NSAIDs treatments before the operation * Used enzyme inhibitor (such as Ketoconazole, Fluconazole, Itraconazole), enzyme inducer (such as Rifampicin, Phenytoin sodium, Carbamazepine, Dexamethasone), anticoagulant (such as Warfarin, Aspirin) and other drugs which increase the drug toxicity (such as Erythromycin, Clarithromycin, Cyclosporin Ciclosporin, ACE inhibitor or Diuretics, Lithium) from the first 3 days before the operation to postoperative observation period * Blood transfusion, hemodilution measures in the operation * Infection of the incision