Objective To evaluate the effect of sevoflurane on activation of nuclear factor kappa B (NF-κB) during brain injury induced by hemorrhagic shock (HS) in pigs.Methods Thirty-two adult male Bama miniature pigs,aged 6 months,weighing 22-25 kg,were divided into 4 groups (n=8 each) using a random number table:sham operation group (group Sham),HS group,sevoflurane preconditioning group (group Sev-Pre) and sevoflurane postconditioning group (group Sev-Post).The animals were anesthetized,and tracheostomized and mechanically ventilated.In group Sham,the bilateral femoral arteries and internal jugular veins were only cannulated.HS was induced by removing 40％ of blood volume within 15 min (30 ml/kg) via the right femoral artery and maintaining at this level for 1 h before resuscitation in HS,Sev-Pre and Sev-Post groups.In group Sev-Pre,2％ sevoflurane was inhaled for 30 min,and then HS was induced.In group Sev-Post,2％ sevoflurane was inhaled for 30 min starting from the time point immediately after HS was induced.Immediately before establishment of the model and at 30,60,90,120,180 and 240 min of HS (T1-6),blood samples from the jugular vein were collected for determination of serum interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) concentrations by enzymelinked immunosorbent assay.At 4 h of HS,the rats were sacrificed,and brains were removed for microscopic examination of hippocampal CA1 region (using haematoxylin and eosin staining) and for determination of the expression of NF-κB in nucleoprotein (by Western blot).Results Compared with group Sham,the concentrations of serum IL-1β and TNF-α were significantly increased at T2-6,and the expression of NF-κB in nucleoprotein in hippocampal CA1 region was up-regulated in HS,Sev-Pre and Sev-Post groups (P＜0.05).Compared with group HS,the concentrations of serum IL-1β and TNF-α were significantly decreased at T3-6,and the expression of NF-κB in nucleoprotein in hippocampal CA1 region was down-regulated in Sev-Pre and Sev-Post groups (P＜0.05).There were no significant differences between group SevPre and group Sev-Post in concentrations of serum IL-1β and TNF-α and expression of NF-κB in nucleoprotein in hippocampal CA1 region (P＞0.05).The pathologic changes were significantly attenuated in SevPre and Sev-Post groups as compared with group HS.Conclusion The mechanism by which sevoflurane attenuates brain injury induced by HS may be related to inhibition of NF-κB activation and reduction of inflammatory responses in pigs.