INCREASED ANTI-TUMOR ACTIVITY OF CHEMOTHERAPEUTIC AGENTS COMBINED WITH DIRECT CURRENT AGAINST TRANSPLANTED TUMOR

1989 Fiscal Year Final Research Report Summary

• Project/Area Number: 62570670
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Cerebral neurosurgery
• Research Institution: Toho University
• Principal Investigator: YOSHII Nobuo Toho University, 医学部, 教授 (60057453)
• Co-Investigator(Kenkyū-buntansha): 溝上 徹 東邦大学, 医学部, 助手 (00157520)
• Project Period (FY): 1987 – 1989
• Keywords: direct current / malignant tumor / chemotherapy

Research Abstract

Immediate and prolonged effects of constant direct current were investigated in mice which were transplanted malignant tumor (fibrosarcoma and others) into the thigh. Animals were inserted electrodes into the tumor and/or normal tissue surrounding the tumor and direct current was applied. Growth of tumor was followed up after directcurrent treatment(DC). Doubling time of the tumor was measured and pathological examination tumor performed just after the DC. Growth delay of the tumor was obtained after the DC, when the number of electrodes were increased in the tumor longer growth delay was obtained. Pathologically 3 zones such as necrosis, necrobiosis and pychnotic change.
The direct current therapy(D.C.T.) (0.6mA, 120min) alone was effective to regress tumor, but tumor was not eradicated by D.C.T.alone. Cyclophosphamide (CPA,100mg/kg) could markedly reduce the FSa tumor size, but all tumor regrew finally. When D.C.T. was combined with CPA(100mg/kg), the therapeutic response of FSA tumor was enhanced in mice which were inserted cathode into tumor. For example, in mice receiving direct current (0.6mA, 120 minutes), the cure rate was 70% compared with 30% by the similar treatment results as the full dose of CPA alone. That is, D.C.T. will be able to reduce the dose of chemotherapeutic agents. Combination of D.C.T. and doxorubicin was not so effective as CPA, but showed the similar results. The experimental in the tumor and makes the drugs more effective.