Changes in volume of mouse liver mitochondria after exposure to nanosecond pulsed-periodic microwave and x-rays

The effect of nanosecond pulse-periodic microwave (RPMs) and pulse-periodic Xrayson the liver mitochondria of mice was investigated. Isolated mitochondria frommouse liver were extracted by standard method of differential centrifugation. The mitochondrialsuspension irradiated 4000 microwave pulses (carrier frequency of 10 GHz,the pulse duration at half-power level of 100 ns, repetition rate of 10-22 pulses per second,the peak power density ranged from 70 to 1500 W/cm2) or pulse-periodic X-rays(the photon energy of 90120 keV, pulse duration of 4 ns, repetition rate of 10-22 pulsesper second, dose per pulse ranged from 0,3 to 2 mR per pulse, and the total absorbeddose of 80 mGy) were tested. The source RPMs used laboratory pulse generator basedon MI-505 magnetron, as a source of pulse-periodic X-rays served accelerator Sinus 150(Tomsk). As impact indicators used an optical density of the suspension of mitochondria,showing the volumetric characteristics of these organelles. It was revealed that after irradiationa volume of mitochondria in suspension may vary. Effect depended on the pulserepetition frequency, the intensity or dose of exposure, the nature of the factor, as well asthe absence or presence of calcium ions in the incubation medium. The effect of RPMsand X-rays irradiation of mitochondria in a calcium medium was significantly higher ascompared with calcium free incubation medium. It could be seen as reducing the volumeof mitochondria (in most cases) so their swelling after the exposure. The reasons for thedecline of volume of mitochondria could be breaks in the inner membrane of mitochondria.That breaks provided not compensated exit of ions from the matrix, which initiatedthe water outflow from the mitochondria. Swelling may be due to input cations (K+,Ca2+) through nonspecific pores in conformity with the electric field gradient. Cationsaccumulate in the matrix with the simultaneous accumulation of phosphate anion. It isknown that Ca2+ ions have a dual effect on the mitochondria function: a) stimulate oxidativeprocesses and b) open the pores in the mitochondrial nonspecific permeability. As aresult of this ions accumulation the osmotic pressure within mitochondria increases andit leads to the entrance of water into the mitochondria and swelling. This may be causedby the modulating influence of pulse-periodic microwave and X-rays on the sensitivity ofnonspecific permeability of mitochondria inner membrane to calcium ions.

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