Antitumor Effects on Mice with S180 Solid Tumor Treated by Topical IL-12 and Its Mechanism

Objectives To study the antitumor function and mechanism of IL-12 in treating S180 solid tumors in mice.Methods The tumor-bearing mice which were inoculated with S180 cells(1×107/ml) subcutaneously in the left hind limb were divided into two groups:NS control group and IL-12 treatment group.And NS,IL-12 were respectively given to the mice of two groups.The ocular blood was removed from the mouse of each group on the 28th day to analyze.Then CD3+T,CD4+T,CD8+T and the ratio of CD4/CD8 of peripheral blood was analyzed with FCM,and tumor tissue was dissected completely for weighting and calculating the inhibition rate and index.The regular diet and physical conditions of the remaining mice were observed,and their tumor size was measured.Results On the 14th day,tumor size of NS control group,IL-12 group respectively got to(8.52±0.46) mm,(7.56±0.09) mm.Then it began to reduce in the IL-12 group.On the 27th day,tumor size was(5.12±1.56) mm and significantly less than that of NS control group(15.34±3.18) mm(P0.01).The tumor inhibition rate of IL-12 group was(31.85±7.24)%,significantly higher than that of NS group(P0.01).Tumor index of NS control group was 7.67 ± 0.67 and tumor index of IL-12 group was 5.51±1.35,which was significantly lower than that of NS control group(P0.01).CD3+T,CD4+T,CD8+T cells in mice blood of IL-12 group were all higher than that of NS control group.Tumor cells of mice in NS group had no significant necrosis,and Mitosis was observed.Tumor tissue of mice in IL-12 group had significant necrosis with most karyopyknosis and cell debris,but lymphocytes and macrophages between tumor cells rarely seen. Conclusions IL-12 has apparente effects in anti-tumor immune response.And it demonstrats that IL-12 relates to the mechanism of changing cell subpopulation and leading apotosis.