| Research Abstract |
Induced colorectal carcinomas in BAIB/c mice by 1, 2-dimetylhydrazine, 30mg/kg sc 1/wk 28wk or 50mg/kg sc 1/wk 28wk. 4 tumors of them were inoculated into subcutaneous tissue of BALB/c nude mice and maintained. Tumor cell suspensions, 100 cells/ml, 1000cells/ml and 10000cells/ml, were made. I injected 0.1ml of these cell suspensions into a vein of BALB/c mouse, in order to make metastatic nodes in the lungs. 10wks after each injections, I sacrificed all mice and counted number of nodes in the lungs. But in this experiment, I could not get demonstrable results.
Then I changed cell line to the colon26, and number of cells, which were injected same as above, were 10cells, 20cells, 40cells, or 80cells. In the lungs of sacrificed mice after 12wks of each injections, I found 0 to 8 (av. 4. 25 +-3.28) nodes. HT-29, human cancer cell line, was prepared same way and injected into a vein of BALB/c nude mouse. Number of injected cells and wks of sacrilege were same as colon26. In this research, I used these plans as syngeneic or xenogeneic models of pulmonary metastasis of colorectal cancer.
Cimetidine (CIM), one of the H2-blockers, was given per os, dissolved in drinking water. Estimated doses (mg/kg/mouse/day) were 0, 40, 80 and 160: CIM were given from 2 days before each tumor injection and given continuously until the day of sacrilege. I found some tendency of suppression of metastasis in 80mg and 160mg groups of both syngeneic and xenogeneic models. But statistically these detas were not sufficient.
In both models, 4 wks after tumor injection, 5fluorouracil(5FU) was given intraperitoneally once a day for a wk. Each doses were 0, 50, 100, 500mg/kg/day/mouse. In this plan, I tested the efficacy of 5FU to micro-pulmonary metastasis. But in this plan, I could not get demonstrable results.
In the next study, singled dose of 5FU, 100mg/kg/mouse/day, was given as the way and 4 doses of CIM were given as the same way. The synergic effect of 5FU and CIM is being analysed.
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