Oxygen tension in mouse muscle tissue after x-ray irradiation with lethal doses.

Abstract

A number of authors have occupied themselves with the changes in the respiration gas exchange of laboratory animals after x-irradiation, although, the results obtained have not been uniform (Kirschner, Prosser and Quastler 1949, Mole 1953, Novak 1954, Smith, Buddington and Grenan 1952, Strubelt 1965). Changes in the oxygen tension in tissue during whole-body irradiation have been described by Vacek, DavidovA and Hosek (1964). Little attention has been paid to the changes of oxygen tension in tissues in the course of irradiation disease. The only estimations, dealing with the changes of oxygen tension in rabbit brain tissue after whole-body irradiation, have been carried out by Snezhko (1958) and Zagoskin and Lainger (1964). Zagoskin found a decrease of oxygen tension in the brain of a rabbit beginning with the second week after exposure to 1500 R. The present experiments followed the changes of oxygen tension in the muscular tissue of mouse in the course of the acute post-irradiative syndrome. The experiments were performed on 4-month-old mice, males, of non-inbred H strain, average body-weight 27-4±0-6 g. The animals, given Larsen diet and water ad libitum, were given whole-body irradiation on a TUR apparatus, at 200 kv, 20 mA, filter 05 mm Cu, mm Al, dose-rate 85 R/min, total exposure 1025 R (death between 5th and 9th day following exposure) and 850 R (death between 8th and 13th day after irradiation). The oxygen tension in the tissues was measured on the animals without narcosis, after the mice had been tied to an asbestos plate, preventing higher thermic losses. The body temperature of the mice was maintained at 36-5 to 375°c (measured rectally) by heating from outside. The oxygen tension was measured at inhalation of air or 100 per cent oxygen. In the group of animals irradiated at 1025 R, the oxygen tension measurements (inhalation of air) were carried out 30 min after the application of thiopental narcosis (1 mg/10 g, i.p.) to exclude the possibility of modification of post-irradiation reactions due to the stressing influence of the experimental manipulation. For measurement of the oxygen tension a modified closed Clark's electrode was used (Vacek 1965), where the cathode was formed of a gold wire of 0.3 mm in diameter, insulated with ' Epoxy' resin. The anode consisted of a silver wire of 05 mm in diameter, electrolytically coated with an Ag2 O layer. As