Electrophysiological Activity and Survival Rate of Rats Nervous Tissue Cells Depends on D/H Isotopic Composition of Medium

Abstract

The deuterium content modification in an organism has a neuroprotective effect during the hypoxia model, affecting anxiety, memory and stress resistance. The aim of this work was to elucidate the possible mechanisms of the medium D/H composition modification on nerve cells. We studied the effect of an incubation medium with a 50 ppm deuterium content compared to a medium with 150 ppm on: (1) the activity of Wistar rats' hippocampus CA1 field neurons, (2) the level of cultured cerebellar neuron death during glucose deprivation and temperature stress, (3) mitochondrial membrane potential (MMP) and the generation of reactive oxygen species in cultures of cerebellar neurons. The results of the analysis showed that the incubation of hippocampal sections in a medium with a 50 ppm deuterium reduced the amplitude of the pop-spike. The restoration of neuron activity was observed when sections were returned to the incubation medium with a 150 ppm deuterium content. An environment with a 50 ppm deuterium did not significantly affect the level of reactive oxygen species in neuron cultures, while MMP decreased by 16-20%. In experiments with glucose deprivation and temperature stress, the medium with 50 ppm increased the death of neurons. Thus, a short exposure of nerve cells in the medium with 50 ppm deuterium acts as an additional stressful factor, which is possibly associated with the violation of the cell energy balance. The decrease in the mitochondrial membrane potential, which is known to be associated with ATP synthesis, indicates that this effect may be associated with the cell energy imbalance. The decrease in the activity of the CA1 field hippocampal neurons may reflect reversible adaptive changes in the operation of fast-reacting ion channels.

Keywords: cerebellum neurons; deuterium-depleted water; glucose deprivation; rats.

Figure 1

Decrease in the induced activity of neurons in the CA1 part of the hippocampus during incubation in a medium with a low deuterium content. Note: on the Y-axis, the pop-spike amplitude is presented as a percentage in relation to the original average value. ISS1—incubation salt solution prepared in water with a natural deuterium content (150 ppm). ISS—incubation salt solution prepared in water with a low content of deuterium (50 ppm). The arrow indicates the effect of different incubation solutions.

Figure 2

Comparison of the amplitude of focal response, expressed as a percentage in reference to the initial average of the responses (ISS1). Note: ISS1 is an incubation salt solution prepared in water with a natural deuterium content (150 ppm). ISS2 is an incubation salt solution prepared in water with a low content of deuterium (50 ppm). * p < 0.05 relative to ISS1—control group.

Figure 3

Influence of the medium with different deuterium content on the value of mitochondrial membrane potential in cultured neurons of the rat cerebellum. Note: on the Y-axis, the intensity of the fluorescence as a percentage is shown. Data are presented as M ± m as a percentage of 150 ppm at a 0 μM concentration of succinate.

Figure 4

The death rate of cerebellum neurons, depending on the temperature and concentration of succinate for ISS—150 ppm. Comparison refers to the points of the 150 ppm—0 μM succinate (100%). Data are represented by M ± m. * p < 0.05 in relation to the point of 150 ppm. Note: 1—ISS is 150 ppm, 0 μM succinate; 2—ISS is 150 ppm, 25 μM succinate; 3—ISS is 150 ppm, 50 μM succinate; 4—ISS is 150 ppm, 100 μM succinate; 5—ISS is 150 ppm, 200 μM succinate.

Figure 5

The death rate of cerebellum neurons depending on temperature and succinate concentration for ISS—50 ppm. Note: The values are compared in reference to points 150 ppm—0 μM. Data are represented by M ± m. * p < 0.05 in relation to the point of 150 ppm; # p < 0.05 is the comparison between points 150 and 50 with the same concentration of succinate. Note: 1—ISS is 50 ppm, 0 μM succinate; 2—ISS is 50 ppm, 25 μM succinate; 3—ISS is 50 ppm, 50 μM succinate; 4—ISS is 50 ppm, 100 μM succinate; 5—ISS is 50 ppm, 200 μM succinate.