To study the effects of repeated treatment with weak microwaves and diet with antioxidants (beta-carotene, alpha-tocopherol, and ubiquinone Q 9) on production of tumor necrosis factor in macrophages and T lymphocytes of healthy and tumor-bearing mice.
Feeding and microwave exposure were started on day 1 after transplantation of cancer cells. The animal cancer model was produced by subcutaneous injection of 2 x 105 Ehrlich ascites carcinoma cells in one hind limb. The mice were killed by decapitation of days 7, 14, and 30 after transplantation of cancer cells.
Microwave exposure and antioxidant diet stimulated production of tumor necrosis factor in cells from healthy animals. At early stages, tumor growth induced tumor necrosis factor production in cells; however, this effect decreased as tumors grew. In tumor-bearing mice exposed to microwaves, tumor necrosis factor production was higher than in unexposed tumor-bearing animals.
Oppositely, antioxidant diet induced tumor necrosis factor production in healthy animals but did not affect tumor necrosis factor secretion in tumor-bearing mice. Accordingly, prolonged treatment of tumor-bearing mice to microwaves, but not to antioxidant diet, decreased tumor growth rate and increased overall animal longevity.
These data suggest that diminished tumor growth rate due to extremely low-level microwave exposure of mice carrying tumors, at least in part, was caused by enhancement in tumor necrosis factor production and accumulation of plasma tumor necrosis factor.