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Effect of Heat and Ionizing Radiation on Normal and Neoplastic Tissue of the C3H Mouse

1975; Radiation Research Society; Volume: 63; Issue: 2 Linguagem: Inglês

10.2307/3574160

1938-5404

Donald Ε. Thrall, Edward L. Gillette, William C. Dewey,

Virus-based gene therapy research

THRALL, D. E., GILLETTE, E. L., DEWEY, W. C. Effect of Heat and Ionizing Radiation on Normal and Neoplastic Tissue of the C3H Mouse. Radiat. Res. 63, 363-377 (1975). The radiation response of the skin of the C3H mouse was evaluated in terms of the dose of radiation required to produce moist desquamation completely surrounding the lower aspect of the hind leg by 21 days following irradiation (DD50-21). Irradiation of the leg under various conditions of local tissue oxygenation indicated that when the animals were breathing air (ambient conditions), the cells in the skin were not fully oxygenated. Heat was administered by immersing the leg for 15 min in 44.50C water either immediately prior to or immediately following irradiation under various conditions of local tissue oxygenation. Heat administered following irradiation reduced the DD50-21 values by 724 rad for hyperbaric 02, 1210 rad for ambient, and 1656 rad for hypoxic conditions. Approximately these same rad equivalents were observed when heat was administered prior to irradiation, under hyperbaric 02 and hypoxic conditions. However, administration of heat prior to irradiation under ambient conditions sensitized the cells to the effects of ionizing radiation. This sensitization was assumed to result from heat causing an increase in local tissue oxygenation prior to and at the time of irradiation. The effect of the heat dose administered under acute hypoxic conditions immediately prior to acute hypoxic irradiation was not significantly different from the protocol where heat was administered under ambient conditions immediately prior to acute hypoxic irradiation. This indicates an independence of the magnitude of the heat effect on the tissue oxygenation status at the time of heating. The response of the C3H mouse mammary adenocarcinoma to combined wet heat (A) and X-radiation (X) administered under either hypoxic, ambient or hyperbaric 02 conditions of local tissue oxygenation was studied.