Influence of a single low-dose cyclophosphamide on CD4~+CD25~+Treg cells in mice and it′s anti-tumor immunity

Objective To explore the effect of a single low-dose injection of conventional chemotherapy drug cyclophosphamide(CTX) on CD4+CD25+Treg cells in mice and it′s anti-tumor effect.Methods Twenty C57BL/6 mice were divided into two groups,twenty mice in each group.The mice in CTX group were injected with CTX(20 mg·kg-1 dissolved in 0.2 mL saline) by intraperitoneal injection,and the mice in control group were injected with 0.2 mL saline by intraperitoneal injection.All of mice were given 0.5 mL cell suspension(including 2×106 RMA tumor cells) by subcutaneous injection after three days and were observed twenty days.3-2,5-diphenyl-tetrazolium salt bromine was used to detect the expression of lymphocyte proliferation by Con A-induced in the lymphocytes of mice spleen.All mice were killed after the four days were intraperitoneal injected.The relative amount of CD4+CD25+Treg cells in the spleen of mice were detected by flow cytometry in the aseptic state;at the same time,the change of expression of scurfin protein in the spleen of mice were detected by western blotting.Results The percentage of CD4+CD25+Treg cells account for lymphocytes in CTX group was significantly lower than that in control group(P0.05);The density of scurfin protein expression in CTX group was significantly lower than that in control group(P0.05);The incidence of tumors in mice in CTX group was significantly lower than that in control group(P0.05);The weight of tumors after was attacked by tumor in mice in CTX group was significantly lower than that in control group(P0.05);A tumor was found in control group mice in 5th days after inoculation,but this time was extended to the eighth days after inoculation in CTX group;the curve of tumor growth is more steep in control group;and the curve is flat in CTX group relatively.The proliferation of lymphocyte in CTX group was higher significantly(P0.05).Conclusion A single low-dose CTX can improve the immune function and have some anti-tumor effects,this provides an experiment basis for the clinical tumor therapy.