The Lymph Node Targeted Chemotherapy For Colorectal Cancer By Drug-loading Activated Carbon Nanoparticles In Mice

Objective To establish lymph node metastasis model of colorectal cancer in mice.Methods Colon 26 cell suspension was subcutaneously implanted in paw pads of 10 Balb/C mice, respectively. The situation of vigor and diet of mice and growth of implanted tumors as well as the metastasis of popliteal fossa lymph nodes were observed. Mice were executed after 42 days, and tumor specimens in paw pads were taken out for routine pathological examinations. Popliteal fossa lymph nodes were finely grinded and digested, then cultured in RPMI-1640 with 10% fetal bovine serum. The growth of tumor cells was observed under microscope. Once attached cells were observed, cell climbing slices were then prepared for immunocellular chemistry.Results The growth of tumor in paw pads was observed in all mice with a latent period of 10 to 12 days. Pathological findings showed that the tissue structure of tumor in paw pads was similar to those for mouse colorectal carcinoma. During the cell culture, cell attachments from 8 lymph nodes cultures were obtained. The positive expression of carcino embryonic antigen in cell intracytoplasm was observed by immunocellular chemistry. The rate of lymph node metastasis was 80%.Conclusions The lymph node metastasis model of colorectal cancer was successfully established in mice. Objective To investigate the application effect of the lymph node targeted chemotherapy for colorectal cancer by drug-loading activated carbon nanoparticles and to observe synergistic cancer-fighting effect of two kinds of chemotherapy drugs, in order to further clarify the mechanism of the lymph node targeted chemotherapy for colorectal cancer and to provide solid theoretical foundation on reducing colorectal cancer recurrence and lymph node metastasis.Methods Colon 26 cell suspension was subcutaneously implanted in paw pads of 50 Balb/C mice to establish lymph node metastasis model of colorectal cancer. Forty-six mice successfully prepared with homograft colorectal carcinoma were randomly divided into 5 groups, the control group (A group, 6 mice), oxaliplatin group (B group, 10 mice), fluorouracil-activated carbon group (C group, 10 mice), oxaliplatin-activated carbon group (D group, 10 mice) and combined treatment group (E group, 10 mice). The situation of vigor, diet and weight of mice as well as tumor in paw pads was observed during chemotherapy. Mice were executed after 48 hours, annexin V/PI was used to measure the apoptosis rate of the implanted tumor in paw pads by flow cytometry. TUNEL assay was used to inspect the apoptosis index of metastasis tumor on popliteal fossa lymph nodes. Experimental data were analyzed by statistical method.Results Vigor, diet and weight of mice in B group decreased obviously and two of them were dead, whereas these parameters in other groups did not change significantly. There were skin erosions on paw pads in B group, whereas the skin was intact on paw pads in other groups. Analytical results of flow cytometry were as follows, the cellular apoptosis of implanted tumor in paw pads in C, D and E group were obviously high compared with A or B group (p﹤0.05), respectively; those in C and D group also showed statistical difference compared with E group (p﹤0.05). Test results of TUNEL assay showed that the cellular apoptosis of metastasis tumor on lymph node in C, D and E group were significantly high compared with A or B group (p﹤0.05), respectively.Conclusions In the study of the lymph node targeted chemotherapy for colorectal cancer by drug-loading activated carbon nanoparticles, chemotherapy drugs significantly induced the cellular apoptosis of implanted tumor and metastasis tumor of lymph nodes by local injection in transplanted tumor. There was synergistic cancer-fighting effect between fluorouracil and oxaliplatin. Activated carbon nanoparticles not only improved cancer-fighting effect and as well reduced the toxicity of chemotherapy drugs. The lymph node targeted chemotherapy could be a kind of potential therapy.