Вплив донора сірководню на варіабельність серцевого ритму і жирнокислотний склад фосфоліпідів міокарда щурів за умов дії малих доз іонізуючого випромінювання

Abstract

Виявлені зміни параметрів варіабельності серцевого ритму (ВСР) щурів через 30 хв. та 1 добу після введення NaHS дозою 7,4 мг/кг свідчать про активацію всіх ланок регуляторних систем з переважаючою мобілізацією парасимпатичної нервової системи. Зміни регуляторних процесів супроводжуються модифікацією жирнокислотного складу фосфоліпідів тканин міокарда та печінки, що полягає у збільшенні співвідношення омега-3/омега-6 ПНЖК. Через 1 добу після опромінення дозою 2 Гр встановлено зниження омега-3/ омега-6 ПНЖК порівняно з контролем, а також істотне зменшення спектральних і статистичних показників ВСР, що вказує на пригнічення активності всіх ланок регуляторних систем. Ефект попереднього до дії радіації введення NaHS виявляється в зменшенні напруження регуляторних процесів, частковому покращенні про- філю жирнокислотного складу фосфоліпідів міокарда, печінки.

Выявленные изменения параметров вариабельности сердечного ритма (ВСР) крыс через 30 мин. и 1 сутки после введения NaHS в дозе 7,4 мг/кг свидетельствуют об активации различных звеньев регуляторных систем с преобладающей мобилизацией парасимпатической нервной системы. Изменения регуляторных процессов сопровождаются модификацией жирнокислотного состава фосфолипидов тканей миокарда и печени, которая состоит в увеличении соотношения омега-3/омега-6 ПНЖК. Через 1 сутки после облучения в дозе 2 Гр установлено снижение соотношения омега-3/омега-6 ПНЖК относительно контроля, а также существенное уменьшение спектральных и статистических показателей ВСР, что указывает на угнетение активности всех звеньев регуляторных систем. Эффект предварительного к действию радиации введения NaHS состоит в уменьшении напряжения регуляторных процессов, частичном улучшении профиля жирнокис- лотного состава фосфолипидов миокарда и печени.

The aim of our study was to study effects of exogenous administration of a hydrogen sulfide donor NaHS on the heart rate variability (HRV) and the fatty acid composition of phospholipids of the heart tissues in rats under the influence of ionizing radiation. Purpose and methods of research. Experimental studies were performed on 50 sexually mature male rats weighing 180-200 g. All experiments were carried out in compliance with the principles of bioethics in accordance with the provisions of the European Convention for the protection of vertebrate animals used for experimental and other scientific purposes (Strasbourg, 1986). NaHS solution was administered intraperitoneally at a dose of 7,4 mg/ kg (Sigma Aldrich, USA). The irradiation of animals was performed in a single-fraction total dose of 2 Gy. We recorded a peripheral pulse non-invasively in non-narcotic animals for the purpose of the HRV analysis. Determination of the fatty acid composition of phospholipids in the heart muscle and liver was performed by gas-liquid chromatography. Results and discussion. As a result it was found, that the total power of the spectrum has increased in comparison to the control group due to the increase of spectral power in all frequency bands, significantly 30 minutes after the administration of the H2S donor. Also, the increased spectral power in the range of high frequency oscillations correlates was detected with rise of CV, SDNN, RMSSD, that, in general, testifies to the activation of the autonomous circuit of regulation of cardiac activity. The results of HRV after 24 h of administration of NaHS have shown noted maintenance of a high level of TP that exceeded the control value, however, it decreased after the influence of hydrogen sulfide on the 30th minute. The growth of statistical parameters of HRV on vs control data was also noted, which indicates an increase in the tonus of the parasympathetic nervous system (PSNS), but it was in a lesser degree of severity than data of rats which was recorded on the 30th minute. Thus, on the 1st day after administration of NaHS, there was a prolonged effect in comparison to that on the initial (30 min) period of exposure to the hydrogen sulfide donor, which ensures the maintenance of increased activity of regulatory processes. One day after total body radiation (TBR) at a dose of 2 Gy, TP decreases in twice was established compared to the control group. The decrease in power in all spectrum ranges was recorded: LF, MF and HF. This data indicates on a significant inhibition of the activity of all parts of regulatory systems. The reduction of HRV time parameters (SDNN, CV, RMSSD) characterizes inhibition of PSNS activity. Thus, the reduction of the total effect of autonomic regulation by SDNN, RMSSD, CV correlated with the reduced total level of activity of regulatory processes by the spectral index of TP and indicated the activation of central regulatory systems. Under the influence of radiation on the background of administration NaHS, it was found that the values of time indexes have increased significantly relative to radiation and almost reached the baseline. The previous administration of NaHS before radiation led to a less pronounced reduction in TP than with radiation alone, indicating maintaining a much higher level of regulatory processes in these conditions than radiation. Thus, the total power of the spectrum 1 day after irradiation with the background of administration of a donor hydrogen sulfide was reduced relative to the results of control, but was significantly higher than at single radiation. Also, it has been established that the effect of a hydrogen sulfide donor (NaHS) in 30 minutes after its introduction leads to increase in the level of omega-3 and a decrease in the level of omega-6 PUFA phospholipids in myocardium vs control group. With such changes in the composition of PUFA, the ratio of omega-3/omega-6 was significantly increased in myocardial and liver tissues. One day after NaHS administration, the ratio of omega-3/omega-6 remains significantly higher than in control group in both tissues, despite the tendency to decrease of previous lifetime of hydrogen sulfide donor. It has been established that under the influence of ionizing irradiation (after 24 hours) the ratio of omega-3/omega-6 were significantly lower in comparison with control group in myocardium and liver tissues. According to the pre-radiation exposure to NaHS, a tendency towards an increase in the ratio of omega-3/ omega-6 to the ionizing radiation effect was observed, but their values did not reach the level of control. Conclusions. The obtained results indicate improvement of the adaptation processes to the action of radiation under the influence of H2S, which consists in the activation of various links of regulatory systems with the prevailing mobilization of the parasympathetic nervous system and moderate activation of ergotropic processes, and partial improvement of the fatty acid composition of the phospholipids in the myocardium and liver.