Current research on the balanced status of cellular metabolism and energy of vital organs under the conditions of extreme factors and the participation in these processes of hydrogen sulfide H2S transmitter remains relevant today.
The changes in the activity of enzymes of energy metabolism in the liver and heart tissues of animals were studied under the conditions of introduction hydrogen sulfide donor and the effect of radiation.
The studies were conducted on sexually mature male rats weighing 180-200 g. Animals were divided into control and four experimental groups, each of 8 rats. Hydrogen sulphide (NaHS) donor was injected at a dose of 7.4 mg/kg (Sigma Aldrich, USA) for 30 min intraabdominally to rats in the 1st experimental group. In animals of the 2nd, 3rd and 4th groups, the study was conducted through 24 hours, respectively, after administration of the hydrogen sulfide donor (7.4 mg/kg), exposure to ionizing radiation at a dose of 2 Gy and a combined effect of NaHS and ionizing radiation.
The activity of the investigated enzymes: aspartate aminotransferase (ASAT, AST, K.F. 18.104.22.168), malate dehydrogenase (MDH, K.F. 22.214.171.124), lactate dehydrogenase (LDH, K.F. 126.96.36.199), succinate dehydrogenase (SDH, K F. 188.8.131.52), cytochrome c oxidase (CcO, K.F. 184.108.40.206) was determined by spectrophotometric method (Bergmeyer H.U., 1983, SF-46).
It was established that 30 minutes after the introduction of H2S donor in the liver homogenate, the activity of SDH increased on 33 % and CcO increased on 17 % in comparison with control. One day after introduction of NaHS, the activity of these enzymes increased even more – on 45 % and 20 %, respectively. AST activity slightly increased with respect to control values through 30 minutes and 1 day after introduction of hydrogen sulfide donor. A significant disproportionate increase in the activity of SDH and CcO both comparing to control and radiation exposure (on 29 % and 17 % respectively), similar to that of NaHS alone, was established in the liver homogenate under the introduction of H2S donor before radiation exposure. Restoration of LDH activity, which exceeds its value at radiation action in 1,5 times, was established. Activation of MDH on 26 % was also noted for the effect of ionizing radiation. Activity of AST exceeded control on 20 %.
In the heart homogenate a significant increase in the activity of AST (65 %) in 30 minutes and even more (almost 2 times) increase in enzyme activity was observed one day after the introduction of the H2S donor. Under these conditions, activation of MDH has been noted. The effect of ionizing radiation on the background of the introduction of NaHS into the heart tissue leads to a significant increase in the activity of AST (2 times) in relation to control and 40% in relation to the effects of radiation, as well as increase in activity of SDH on 32 % to the control and on 55 % to radiation exposure.
Thus, the use of the H2S donor in the liver, as well as the effect of radiation on the background of its pre-introduction, leads to the activation of FAD-dependent energy formation, as evidenced by increased activity of SDH coupled with a less pronounced increase in the activity of CcO. In the heart tissue under the influence of hydrogen sulfide donor and action of ionizing radiation, the malate-aspartic shuttle mechanism is activated, which provides maintenance of the electrochemical gradient of protons, and, consequently, the increase of the capacity of the respiratory chain.
Keywords: hydrogen sulfide, ionizing radiation, aspartate aminotransferase (AsAT, AST), malate dehydrogenase (MDH), lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), cytochrome c oxidase (CcO)
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