Anti-angiogenesis Mechanism Of Dihydroartemisinin Combined With Metronomic Chemotherapy On H22 Tumor-bearing Mice

Objective To investigate the effect of dihydroartemisinin combined with metronomic chemotherapy against angiogenesis in H22 liver cancer and the possible mechanism of action.Methods The H22 liver cancer mouse model was constructed and randomly divided into model group,metronomic chemotherapy group(CTX,20mg/kg),high-dose dihydroartemisinin combined with metronomic chemotherapy group(CTX+DHA(H),100mg/kg+20mg/kg),medium dose dihydroartemisinin combined with metronomic chemotherapy group(CTX+DHA(M),50mg/kg+20mg/kg),and low dose dihydroartemisinin combined with metronomic chemotherapy group(CTX+DHA(L),25mg/kg+20mg/kg),with 6 mice in each group.The model group was given saline.All groups were administered continuously for 14 days.24 hours after the last dose,eye blood was taken first and then killed,tumor tissue,thymus and spleen were stripped and weighed to calculate the tumor suppression rate,spleen index and thymus index;the expression level of IL-6 and VEGF in peripheral blood was determined by ELISA;the expression level of NF-κB and VEGF protein in tumor tissue;the gene expression level of NF-κB and VEGF by real-time PCR;and the expression level of VEGF protein by microvascular density and mice by immunohistochemistry.Result(1)No significant difference in weight of mice was observed before modeling.After14 days of treatment,there was no significant difference in body weight in each group compared with the model group(P>0.05);(2)Compared with the model group,the CTX group,CTX+DHA(M)group and CTX+DHA(L)group were all lower than the model group(P<0.05).The tumor weight of the CTX+DHA(H)group was significantly lower than that of the model group(P <0.01).The tumor suppression rates ranged of each groups from low to high were 30.45%,35.59%,31.29% and 30.00%,respectively;(3)Compared with the model group,the thymus index of CTX group was lower than the model group(P<0.05),and there was no significant difference among the other groups;the spleen index between all groups,with no statistical significance(P>0.05);(4)On the peripheral blood level,the levels of VEGF and IL-6 in the other four groups mice were significantly reduced compared with the model group(P <0.01).Compared with the CTX group,CTX+DHA(H)and CTX+DHA(M)were lower than in the CTX group(P<0.05),and IL-6 in CTX+DHA(H)was significantly lower than in the CTX group(P<0.01).(5)At the level of protein expression,the other four groups tumor-bearing mice decreased VEGF protein expression in tumors to different degrees compared with the model group,and the difference between CTX group and CTX+DHA(H)group was statistically significant(P<0.05).Compared with the CTX group,the CTX+DHA(H)group and CTX+DHA(M)group were lower than the CTX group(P<0.05).In addition,the CTX+DHA(H)group had less MVD number and VEGF expression(P<0.05),while the number of MVD and VEGF expression in the other groups were relatively reduced,but not significantly different from the model group(P>0.05).(6)At the level of gene expression,the expression of NF-κB gene was lower than that of the model group(P<0.05),and the expression of VEGF genes in the CTX group,CTX+DHA(H)group and CTX+DHA(M)group were decreased to varying degrees(P<0.05).Compared with the CTX group,the expression levels of the VEGF and NF-κB genes in the CTX + DHA(H)group were relatively lower(P<0.05).Conclusion Dihydroartemisinin combined with rhythmogenic chemotherapy has an inhibitory effect on tumor body angiogenesis in H22 tumor-bearing mice,and the mechanism may be related through the downregulation of inflammatory factors to inhibit vascular endothelial growth factor generation.