The model for study of influence Of magnetic fields on biological objects (within the Russian maglev project)

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INTRODUCTION

The main attention in the modern scientific literature is paid to operational developments and problems of magnetic levitation transport systems, the energy analysis of the technologies used and developed, the search for optimal technical solutions for safety. The project "Russian Maglev" (RM) is used the system of static magnetic levitation in contrast to electrodynamic (Maglev) and electromagnetic (Transrapid) levitation systems [1]. In this regard, the issues of medical safety of the "RM" have special features, although in the overall structure of the problems they are given insufficient attention. Therefore, it is important to establish the locations and levels of field characteristics around the "RM", to conduct model medical and biological studies to establish the impact of non-radiation physical fields on various systems of the body, to develop evidence-based proposals and recommendations for the establishment of regulatory norms in this type of transport, to protect against harmful fields effects on passengers and service personnel.

The aim of this work was to study the characteristics of the main sources of static magnetic fields (SMF) used in the technology of "RM" and affecting the human body. The studies in organotypic tissue culture for the differentiated assessment of SMF impact on the organs of different mammalian systems were carried out. It should be noted that the cell and tissue cultures in biological research is increased common as relatively simple model systems is possible to successfully solve many problems the impact of various environmental factors on different organisms.

Organotypic tissue culture is the most appropriate and convenient method for a rapid quantitative assessment by level influenced physical factors on biological objects [2, 3]. This is due to the change in the number of cells is the result of stimulation or inhibition of cell proliferation, and this change serves as a criterion for the primary integral assessment of biological activity, including SMF. The advantage of this method is that the explants retain the same hierarchical subordination of the cellular composition of the tissue, as well as in the whole body. In the organotypic culture the strictly dosed effect directly on the cells by SMF is possible to have. This excludes the effect of the whole body nervous, hormonal and other effects. The classical test system is the organotypic culture of various rat tissues.

MATERIALS AND METHODS

The effect of SMF on cell proliferation processes in organotypic tissue culture from different organs mature male rats of the Wistar population (“collection of laboratory mammals of different taxonomic affiliation”, Pavlov Institute of Physiology RAS supported by the program of bio-resource collections Federal Agency of Science Organizations from Russia) were studied. The 747 explants of the tissues of the cerebral cortex (n=182), spleen (n=184), kidney (n=95), heart (n=96), prostate (n=92) and liver (n=98) were studied in the experiments. Explants were placed in Petri dishes with a nutrient medium pH=7.2 containing saline (0.9 %) 50 ml, MEM 50 ml, fetal bovine serum 10 ml, glucose (5 %) 1 ml, gentamicin (4 %) 0.5 ml. Petri Dishes with explants were placed in a CO₂ incubator at 36,8°C [4, 5].

The experimental Petri Dishes were exposed in a special camera with a magnetizing device consisting two magnetic poles-concentrators (flat ferrite magnets Y22H ($F{e}_2{O}_3\bullet SrC{O}_3$) with an anisotropic magnetic structure and a platform of non-magnetic material for placing Petri dish with explants of the studied tissue. Concentrators formed a spot of homogeneous SMF, the structure and the amount of induction was controlled by the device Teslameter f 4354/1 at the location studied tissue. The magnitude of the intensity and control of the uniformity of the field in the spot was established and regulated by the mutual location of the concentrators. The measurement error did not exceed 2.5 %. Petri dishes with samples of different tissues was placed between the working ends face of the magnet poles where were within three days at a constant temperature and atmosphere with a homogeneous SMF (~200 mT). The value of the SMF induction value in the experiment corresponds to the SMF intensity in the railway car of the project "RM" at one meter from the floor [6].

The data of two experiments for each tissue included the control Petri dishes without SMF exposure and experimental Petri dishes the with SMF were obtained. To quantify the impact of SMF on the development of explants used for morphometric method comparing the control and experimental Petri dishes. For this after the explants were visualized using a microtelevision attachment (series 10, MTN-13, Alpha-Telecom), was calculated area index (AI) using PhotoM 1.2 software.

In the cultivation there is migration cells into the growth zone (GZ) from the Central zone (CZ) of the explant estimated by AI calculating by the formula (1) relationships area (S) the explant (${\text{S}}_{\text{GZ}+\text{CZ}}$) to the area of the central zone ( ${\text{S}}_{\text{CZ}}$).

$AI=\frac{S_{GZ+CZ}}{S_{CZ}}$ (1)

Then, the values of $AI$ were averaged separately for the control $A{I}_C$ and experimental dishes $A{I}_E$. The Average value of $A{I}_C$ was taken as 100 %, and the difference of average values ($\Delta AI$) expressed in percent by the formula (2), demonstrates the amount and direction of influence on proliferation of cells.

$\Delta AI=\frac{A{I}_E-A{I}_C}{A{I}_C}\times 100 \%$ (2)

The reliability of the differences of $AI$ explants in the control and experimental dishes after checking for compliance with the normal distribution of the data was evaluated using t criteria for independent samples. Statistically significant differences were taken at the level of p less than 0.05.

RESULTS AND DISCUSSION

According to previously studied and presented the characteristics of the main sources of SMF in the technology "RM" [6], the magnetic induction exposed to the human body increases from < 1 to 300 mT when approaching the source of MF from 0.7 to 0.1 m, respectively. The data obtained are compared with the current Russian normative and technical documents: SanPiN 2.2.4.3359-16 "Sanitary and epidemiological requirements for physical factors in the workplace" (unfortunately, the regulatory standards in the Russian Federation on transport have not yet been developed). According to the literature data, non-specific reaction by the type of General adaptation syndrome were caused in the human body after exposition of SMF. There is possible specific, similar to the meteotropic, reaction, proceeding with a change in vascular tone. There is a belief that the magnetic factor is not the direct cause of the disease, it only provokes it or contributes to the aggravation of the existing pathological process. People with meteosensitivity may have functional disorders that affect the quality of life. At the same time, the specific dynamics of physiological parameters in different people may be vary [7].

However, the results of screening studies exposure on different organs by SMF the same intensity in the literature could not be found. In addition, only a number of studies have described the study of the characteristics of SMF having the greatest biological effect. There is the most suitable method organotypic tissue culture for the screening study of the action of biologically active factors [8].

According our experimental data uniform SMF with induction of ~200 mT has different effects on the cells of different mammalian tissues. In the Table 1 presents the average values of AI for the explants organotypic tissues culture: liver, heart, prostate, kidneys and we can conclude that proliferative processes are not changed because the values of statistically not significant different from . While SMF depressed cell proliferation of immune spleen tissue and brain cells.

 

Table. The average values of $\mathit{A}\mathit{I}$ for the explants organotypic tissues culture in control ($\mathit{A}{\mathit{I}}_{\mathbf{C}}$)  and experiment ($\mathit{A}{\mathit{I}}_{\mathbf{E}}$ )

	cerebral cortex	spleen	liver	renal	prostate	heart
$A{I}_C,n.u.$	1.6±0.26	1.98±0.62	1.67±0.67	2.11±0.78	1.37±0.2	1.79±0.37
$A{I}_E,n.u.$	1.29±0.12	1.6±0.34	1.66±0.3	1.76±0.32	1.36±0.2	1.78±0.19
Р-value	0.03	0.03	0.83	0.26	0.85	0.65

 

There is decreasing $A{I}_{}$for explants in the experiment compared to the control statistically significantly (P=0.03) for the tissues of the cerebral cortex ($\Delta PI$= –19.7 %) and spleen ($\Delta PI$= –18.9 %).

Despite the above results impact of SMF on living organisms and cells, the long-term practice of SMF application in medical procedures, for example MRI, allowed to publish the works, confirming the safety of SMF application [19, 20]. Although using relatively strong magnetic fields, such procedures can really be safe for patients due to the short duration of magnetic exposure. For the staff, the chronic action of SMF and other harmful factors, allows to neutralize compliance with Sanitary and epidemiological requirements that are non-specific to neutralize the action of SMF [18]. The presented data do not exclude the remote manifestations of SMF by induction 1T exposure for human health [21, 22], although no such effects have been found in other studies [23].

In according to above, there is important to search protection means to reduce the biological effect of SMF on passengers and service men using the transport system "RM". Therefore, in our work we have tried to present the testing model for various neutralization or decrease means of SMF biological effects with the organotypic tissue culture. For this in the 2nd series of experiments, the polypeptides with tissue-specific and stimulating proliferative effect were selected [23, 24] and were introduced into the culture medium for SMF undergone explants. The drug Cortexin^® was added to medium of explants the cerebral cortex and Timalin® was added to medium of explants the spleen. These drugs were added at effective concentration 50 nG/ml. Figure 1 shows to decrease statistically not significant the number of $AI$ ($\Delta AI$= –12.3 %) under the action of Cortexin^® in explants of the cerebral cortex (thus, the effect of SMF decreased overall by 9 %). The increase of AI statistically not significant was observed in the experimental compared to control the Petry dishes with explants of the spleen undergone combined effect of Thymalin^® and SMF ($\Delta AI$ =+13.4 %).

 

Fig. The SMF influence on the cortex (1) and spleen (2) in isolation (dark bars) and in combination with Cortexin® and Timalin® respectively (light bars)

 

The data confirm the functional inhibition of proliferative activity explants of spleen and cerebral cortex under the influence of SMF and the normalization proliferative potential under the influence contained growth factors in the used drugs.

Our data have been compared with the other studied data, as the SMF with induction in the range from hundredth to hundreds of mT in the laboratory is created relatively easy. Currently, there is two main areas for scientist’s attention of research: the actioned mechanisms of SMF on living organisms are searched and the biological effects of weak SMF usually with adverse effects on the body are observed. We will discuss the latter direction in more detail. In a number of studies with MF with similar characteristics were obtained cellular effects. In all studies the inhibition of cell proliferation due to an increase in DNA damage when exposed to SMF induction 970 mT [9] or MF with a frequency of 50 Hz and induction 400 mT [10], stimulation of apoptosis MF with a frequency of 50 Hz and induction of 150 mT [11] and SMF with induction 1Т [13], increased transcription of genes in SMF with induction 100 mT [15] and damaging effect on the cell membrane with induction of SMF 100–300 mT [17] were described.

However, simple decrease as the induction level of SMF 10–1 000 times then the maximum permissible level (according to 2.2.4.3359-16 “Sanitary and epidemiological requirements to physical factors in working places”) does not neutralize the negative effects of SMF at the cells. According to the literature, enhancing proliferation due to inhibition of apoptosis in SMF with induction of 0.6 mT [12], decreasing the adhesive ability of white blood cells in SMF with induction of 0.05–10 mT [14], increasing the intracellular concentration of heat shock proteins in MF with a frequency of 50 Hz and induction of 10–140 µT [16] are observed. In this regard, there is our direction of research studying the damaging effects of MF with the value of induction and measured characteristics around the "RM".

CONCLUSION

It was shown, the people need for protection from MF of "RM" system. On the basis of the research listed in this article, the prospect of using the presented biological model in the development and testing of methods and measures to protect against the adverse effects of MF arising from the operation of the magnetic levitation transport system is created. After substantiation of medical and biological safety at the cellular level of technogenic MF system "RM", it is possible to conduct monitoring studies on real models [26].

The above data allowed us to draw the following conclusions:

1. At the level of the calculated values of the induction of the static magnetic field of the project "Russian Maglev" there is a negative effect on the proliferative activity of the organotypic tissue culture of the cerebral cortex and spleen.
2. The presented biological model of evaluation of the influence of static magnetic fields in the organotypic tissue culture allows to carry out preliminary testing of physical protection means intended for use in the project "Russian Maglev".

About the authors

Artemy V. Rubinsky

Federal State Budgetary Educational Institution of Higher Education Academician I.P. Pavlov First St. Petersburg State Medical University of the Ministry of Healthcare of Russian Federation

Author for correspondence.
Email: rubinskiyav@1spbgmu.ru
ORCID iD: 0000-0003-1041-8745
SPIN-code: 3020-0781

PhD

Russian Federation, 6/8, Lva Tolstogo street, St. Petersburg, 197089

Timur D. Vlasov

Federal State Budgetary Educational Institution of Higher Education Academician I.P. Pavlov First St. Petersburg State Medical University of the Ministry of Healthcare of Russian Federation

Email: tvlasov@yandex.ru
ORCID iD: 0000-0002-6951-7599
SPIN-code: 8367-1246

MD, PhD, Professor

Russian Federation, 6/8, Lva Tolstogo street, St. Petersburg, 197089

Natalia I. Chalisova

Pavlov Institute of Physiology of the Russian Academy of Sciences

Email: ni_chalisova@mail.ru
SPIN-code: 2139-7608

DSc (Biol), PhD, Professor

Russian Federation, 6, Makarova street, St.Petersburg, 199034

References

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