The Effect Of Dexmedetomidine Adjuvant Intravenous Anesthesia On Natural Killer Cells In Surgical Patients

Background: Surgical therapy is the main way of treatment for potentially curablesolid tumors. However, the main cause of postoperative cancer death is tumorrecurrence and metastasis. Natural killer cell (NK cell) is a critical component ofimmune cells, which prevent and inhibit tumor recurrence and metastasis after surgery.During perioperative period the patients’ NK cells number and activity directly affectpostoperative mortality rate. Surgery stress activates the hypothalamic-pituitary-adrenalaxis (HPA) over release catecholamine that decrease the number and activity of NKcells. Anesthesia can attenuate the surgery stress leading decrease of NK cells numberand activity in a certain extent. However, anesthetic drugs themselves affect NK cellsin various degrees. In clinical anesthesia, we get use to combine several kinds drugs,since what different combination will have different effect on NK cells.Dexmedetomidine it is a high selective agonist of α2-adrenergic receptors， which canwidely act on the central nervous system produce sedation, analgesia, anxiolytic andanti-sympathetic effects. It can inhibit positive feedback of HPA under stress andattenuate stress response. In this study, dexmedetomidine as an adjunct anesthetic agentprovides a sedated patient in the preoperative period, reduced need for other analgesicsand anesthetic drugs in the intraoperative period. We investigate the effect ofDexmedetomidine adjuvant intravenous anesthesia on natural killer cells in surgicalpatients.Methods:35patients scheduled for colectomy who were classified as grade Ⅰ orⅡ according to the American Society of Anesthesiologists grading system wereenrolled. They were randomly allocated to receive dexmedetomidine (group Dex) orsaline (group control). The difference of two group is that group Dex usedexmedetomidine to induction and maintainance, while group control use saline. During surgery, we adjusted the doses of propofol and remifentanil according to the BISand maintained it between40dan60. Samples of peripheral blood were taken beforeanesthesia (T1), after the infusion of dexmedetomidine or saline (T2), after theinduction5min (T3), at the end of infusion drugs (T4), after surgery24hours (T5).Blood samples were analyzed to give the number of NK cells.Results: After surgery24hours (T5), the NK cell’s number of group control wereSignificantly less than the group Dex’s (P<0.05). In the group Dex, the number of NKcells at T5is more than at T4. Both of two groups, the number of NK cells were sharplydecrease after induction.Conclusion: both combination of intravenous anesthetics could decrease NK cellsnumber after induction5min. Dexmedetomidine adjuvant intravenous anesthesia mightcontribute to recovery NK cells number.