Effect Of HIIT Pretreatment On The Function Of CD8~+T Cells In Melanoma Mice

Objective:Based on the fact that 2-week HIIT after tumor inoculation can effectively prolong the life span of melanoma mice.This study built an 8-week HIIT in mouse model before B16 cells inoculation,analyzed the functional characteristics of CD8~+T cells in spleen and tumor of mice,and then explored the possible synergistic effect of HIIT before B16 cell inoculation on the"anti-tumor effect of 2-week HIIT after inoculation",in order to further supplement the experimental basis for regular exercise in anti-melanoma.Methods:57 SPF-grade female C57BL/6 mice were used as experimental subjects.Experiment 1:18 mice were divided into tumor group(group T:9)and tumor exercise group(group THs:9),group T without exercise while group THs for 2 weeks of HIIT intervention.Experiment 2:divided into control group(group C:13),tumor exercise group(group TH:13)and long-term exercise tumor group(group HTH:13).Group C was injected with PBS without exercise intervention,and after 8 weeks of HIIT in group HTH,they were inoculated with tumors at the same time as group TH and continued with 2 weeks of HIIT intervention.Flow cytometry was used to detect the percentage of CD8~+T cells and immune checkpoint expression in the spleen and tumor tissues of the three groups of mice,as well as the percentage of CD8~+T cell subtype cells,glucose uptake energy,mitochondrial mass and ROS expression.Results:(1)The survival time of group THs was longer than that of group T(P=0.032<0.05).(2)After 8 weeks of HIIT intervention,the maximum motor speed in group HTH was significantly higher than that in group TH(P=0.001<0.01),group C(P=0.002<0.01),and group HTH before 8 weeks(P=0.016<0.05).(3)In the spleen,the percentage of CD8~+T cells in group HTH was significantly more than that in group TH(P=0.001<0.01)and C group(P=0.012<0.05),while the mean fluorescence intensity of PD-1 in CD8~+T cells was significantly lower than that in group TH(P=0.018<0.05)and group C(P=0.047<0.05).(4)In the spleen,The ratio of Tn cells to CD8~+T cells in group HTH was obviously higher than group TH(P=0.014<0.05)and group C(P=0.000<0.001),while Tm and Te cells was significantly lower than that in group C(Tm:P=0.010<0.05:Te:P=0.007<0.01);the percentage of Tn cells to T cells was significantly higher in group HTH than group TH(P=0.000<0.001)and group C(P=0.000<0.001).The percentage of Tn cells with high mitochondrial mass in group TH was significantly lower than that in group C(P=0.028<0.05),and Tm cells were significantly lower than those in group C(P=0.001<0.01)and group HTH(P=0.038<0.05).The percentage of ROS~+Tn cells in group HTH was higher than group TH(P=0.007<0.01),while the mean fluorescence intensity of ROS~+Te cells in group C was significantly higher than group TH(P=0.027<0.05)and group HTH(P=0.001<0.05).(5)In the tumor,the percentage of Tn and Tm cells with high mitochondrial mass in group HTH was more than that in group TH(Tn:P=0.004<0.01,Tm:P=0.015<0.05),and the mean fluorescence intensity of high mitochondrial cells in Tm cells was significantly higher than group TH(P=0.037<0.05).the mean fluorescence intensity in ROS~+Tn,Tm and Te cells in group HTH were significantly lower than those in group TH(Tn:P=0.014<0.05;Tm:P=0.027<0.05;Te:P=0.015<0.05).Conclusions:(1)HIIT pretreatment could improve the exercise ability of mice.(2)HIIT pretreatment further reduced the inhibition level of CD8~+T cells and increased the amount of CD8~+Tn cells in spleen tissue,it also regulated the aerobic metabolism of CD8~+Tn and CD8~+Tm cells.(3)To some extent,HIIT pretreatment further improved the aerobic metabolic capacity of CD8~+T cell subtype cells in tumor tissue.