Objective To explore the effect of Kupffer cells (KCs) secretion on HCC cells after cryoablation and its mechanism.

Methods Sixteen groups were divided:37℃ control group, three hypothermia groups(0℃, 5℃, 10℃), freeze-thaw necrotic substances group, three combined stimulation group and 8 parallel groups for each group. In the 8 parallel groups, pyrrolidine dithiocarbamate(PDTC) was added, and the final concentration was 100 μmol/ml. The concentration of TNF-α, IL-1β and INF-γ in 16 groups of KCs supernatant were determined by Elisa method. The expression of NF-κB protein in each group was detected by Western blot.

Results The secretion of inflammatory factors TNF-α, IL-1β and INF-γ increased after combined stimulation of KCs with hypothermia and freeze-thaw necrotic substances (P<0.01). The combined stimulation of low temperature (0℃, 5℃, 10℃) and freeze-thaw necrotic substances in the three groups showed superposition effect. Hypothermia stimulation had no significant effect on the expression of NF-κB protein (P>0.05), but the expression of NF-κB protein in the combined stimulation group and freezethaw necrosis substances group were significantly up-regulated (P<0.05). Treated with NF-κB inhibitor, the expression of NF-κB protein and the secretion level of inflammatory factors did not change significantly among 8 parallel groups (P>0.05). The concentrations of TNF-α, IL-1β and INF-γ were positively correlated with the expression of NF-κB protein in the culture medium of KCs (r ≥ 0.870, P=0.000).

Conclusion Freeze-thaw therapy could enhance the function of KCs secretion cytokines, and to a certain extent, it could induce inflammatory response and eliminate tumor cells. The secretion function of KCs may play a role through NF-κB signaling pathway.