To investigate the dose-effect relations among the expression of COX-2 in polymorphonuclear leukocytes (PMNL) and macrophages, systemic and local inflammatory response and postoperative pain

we detect COX-2mRNA, COX-2 protein expression in inflammatory cells and PGE2 concentration in patients with abdominal surgery. The differences of COX-2 expression in PMNL are compared between peripheral blood and partial incision transudate to the same individual, and at the same time, the COX-2 expression differences in PMNL and macrophages, and PGE2 concentration in partial incision transudate also compared interindividually, to show the relevance between the difference and postoperative pain. In addition, the effects of Parecoxib Sodium on COX-2 expression of the amount in PMNL and macrophages are investigated during the development of postoperative inflammatory pain. Finally, we will clear the dose-effect relations among the expression of COX-2 in inflammatory cell, systemic and local inflammatory response 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