Effects of Different Doses of Ketamine on Immune Function and Tumor Metastasis in Rats

【Objective】 To investigate the effects of different doses of ketamine on the immune function and tumor metastasis in rats. 【Methods】 100 Fischer344 male rats were randomly assigned into 5 groups: Normal saline group(group Saline), ketamine 25 mg / kg group(group K25), ketamine 50 mg / kg group(group K50), ketamine100 mg / kg group(group K100), ketamine 200 mg / kg group(group K200). 24 hours after intraperitoneal injection of ketamine or normal saline, 10 rats in each group were picked up randomly to detect of lymphocyte subsets CD3+、CD4+、CD8+、CD4+ / CD8+ and NK cell counts, NK cell activity, The other 10 rats in each group were intravenous injected MADB106 tumor cells. Tumor lung metastases were assessed three weeks later. 【Results】 Compare to group Saline, the numbers of CD3+、CD4+、CD8+ lymphocytes and the ratios of CD4+ / CD8+ showed no significant different in group K25, but decreased significantly in group K200 (P 0.01),and the numbers of CD3 + 、CD4 + lymphocytes were reduced significantly in group K50 and K100 (P 0.05 or P 0.01). Compare to group Saline, the numbers of CD161a+ and NK cell activity of rats decreased significantly in all groups dealt with ketamine(P 0.01 ), while tumor metastases in lung were were dramatically increased (P 0.01). The Pearson correlation coefficient between the doses of ketamine and NK cell activity, NK cell counts, tumor Lung metastases is -0.801、-0.420 and 0.969 separately. 【Conclusion】 Ketamine can suppress the immune function of rat, thus contribution to the susceptibility of tumor metastasis. NK cell activity and tumor Lung metastases are closely related with ketamine doses.