Experimental Study On Thermal Ablation Of Transplanted Liver Cancer Subcutaneously At Different Temperatures In Mice

Objective: To investigate the proper ablation temperature that can induce the maximum anti-tumor immunity by using different temperature saline ablation with subcutaneous liver cancer in mice via observing the survival time and tumor volume,recording the immune cell numbers and heat shock protein expression in lesion.Method: After the subcutaneous tumor model was established in mice, 120 mice were randomly divided into 5 groups, each group had 24 mice. We started experiment when the tumor diameter about 6~8 mm length after 7 to 12 days. Each group were given intratumor injection of 0.15ml saline with different temperatures respectively (50℃,60℃,70℃,100℃).Survival time , tumor size , residual rate of tumor, lymphocyte number, and expression of HSP70 were measured in each group.Results:①Survival time were different in each group(P<0.05), but the mice in 50℃group had the longest survival time.②Compared with conrtol group, tumor volumes in each ablation were reduced significantly(P<0.05), but the 50℃group was the only group without tumor continuing to grow up as compared with the volume before ablation.③Confirmed by HE staining, there were no tumor cell necrosis in the control group, residual rate was 100%; residual tumor cells were found at 1 specimens in 50℃group, residual rate was 16.7%; residual tumor cells were found at 2 specimens in each of the other groups, residual rate was 33.3%.④CD4+ cells number in 50℃group was significant higher than those in other group(sP<0.05). No significant difference of CD8+ cells number was show between 50℃group and control group (P> 0.05), but CD8+ cells number in 50℃group was significant higher than those in other ablation groups (P<0.05). CD4+/CD8+ ratio increased markedly in 50℃group. Compared with conrtol group, the labeling index of HSP70 in each ablation group increased significantly(P<0.05), and labeling index in 50℃group was the highest.Conclusion:Compared with different saline ablation tempereture to subcutaneous liver cancer in mice, ablation with 50℃saline may induce a more intensive antitumor immunity.