Abstract: Objective To observe the effects of dexmedetomidine on levels of tumor necrosis factor-α(TNF-α)，interleukin-6 (IL-6)，serum creatinine(Scr) and blood urea nitrogen (BUN)  in the patients undergoing radical nephrectomy during perioperative period，and to probe the influences of dexmedetomidine on immune function and renal function.Methods Sixty patients with kidney cancer undergoing radical nephrectomy were randomly devided into dexmedetomidine group(n=30) and control group(n=30).The blood samples were taken immediately before induction of anesthesia(T0)，1 h after the beginning of  operation(T1)，at the end of  operation(T2)，1 d after operation(T3) and 3 d after operation(T4) for determining the levels the of TNF-α,IL-6,Scr and BUN.
Results Compared with T0 time point，the levels of serum TNF-α and IL-6 of the patients in dexmedetomidine group had no sianificant differences at
all time points（P>0.05）；the levels of serum TNF-α and IL-6 of the patients in control group were significantly increased at T1-T3 time points (P<0.05).Compared with control group，the levels of serum TNF-α and IL-6 of the patients in dexmedetomidine group were significantly decreased at T1-T3 time points (P<0.05).There were no significant differences of  Scr or BUN  levels between two groups during perioperative period(P>0.05).
Conclusion Continuously intravenous infusion of dexmedetomidine may effectively decrease the levels of serum TNF-α and IL-6 in patients undergoing radical nephrectomy during perioperative period and inhibit the perioperative stress response，and doesn’t have  influence on renal function.

Key words: dexmedetomidine, kidney neoplasms,  , interleukin-6, tumor necrosis factor-&alpha, serum creatinine, blood urea nitrogen