The examination of the effects of electromagnetic fields on heart tissue of rat using optical microscope.
Survival and life on earth depend on the weak and natural electromagnetic fields from which the sun and lightning are two main sources. In recent years, advancement in man-made technology fields with different spectra in science, technology and medicine, has made the scientists and general public worried about the possible biological consequences of these fields. A wide range of health-related researches were conducted in connection with these fields, but definitive results haven't been obtained, so far. Epidemiological studies show that the fields with 60HZ flow and more than 2 mt potency, increase the risk of cancer in living and working environment . On the other hand, the Maximum level of electromagnetic fields announced by World Health Organization (WHO) is 1 mt. Although the exact mechanism of action and effects of electromagnetic fields are still completely unknown, but the background of studies indicate the harmful effect of these waves on different organs in rats. Therefore, recognizing the effects of electromagnetic fields will help with the discovery of their mechanisms of action though further studies are needed to be done.
Considering the increasing usage of electronics in daily life, human being is exposed to electromagnetic field more than ever . Electromagnetic fields have different types that are classified based on their wavelength or frequency. Frequency of these fields is determined based on the type of the supplier. However, the ratio between wavelength and frequency of electromagnetic fields is reversed . These fields are generated by printers, vacuum cleaners, cell phones, TV, hair dryer, electric shaver, microwave ovens and electrical devices, sewing machines, elevators, ferromagnetic in high voltage cables in the electric industry, etc. With the dramatic growth of using computer technology in the world, we should expect more reports about the different types of abnormalities in the human being societies. Most studies show that produced electromagnetic fields are able to create biological disorders. Heart's electrical activity as an important physiological phenomenon can be affected by this field. The mechanisms through which electromagnetic fields can affect the heart's electrical activity, changes the heart's tissue and subsequently the electrical conductivity. Electromagnetic field has negative impact on bone marrow and blood cells of rat and may cause leukopenia, lymphopenia and a slight increase in the peripheral blood erythrocyte. Reduced growth and cell division, differentiation of granulocytes in both male and female and reduced amount of stem cells in bone marrow of female mice with low-frequency electromagnetic field have been reported .The effects of electromagnetic field on heart rate show the decrease and mutability of the heart rate [3,18]. Jeong et al, reported that electromagnetic field with too low intensity can weaken the increase of heart rate by affecting ventricular repolarization; maybe the effect of this down regulation on the cardiovascular responses is created by inducing agonists of sympathetic system . Considering that the circulatory system is the main connecting and feeding system of the body tissues, it is very sensitive and any malfunction of this system can create disturbances in other organs, as well . Thus, the aim of this study is to examine the effects of the electromagnetic filed on the heart tissue.
Methods and Materials
In this study, thirty 5-week-old rats weighting between 100-150 gr were used. Rats were divided in two groups (test and control) and in each group 15 rats were studied. Rats in test group were exposed to electromagnetic field with 1mt intensity, 8-hour-daily for 2 months. After 2 months, rats were killed using anesthesia and their heart tissue was sampled. Environmental and feeding conditions in control group were similar to test group and did not just influence the electromagnetic field. In this group, rats were killed using anesthesia and their heart tissue was sampled, like the same occurred in the test group after 2 months.
Electromagnetic field supplier device:
For performing the test, electromagnetic field supplier device which was producing 1mt intensity and was designed in histology department, was used. Field generating device had been built according to Helmholtz's coil theory, that in connection with this selection, some cases were determined, such as the need to achieve a steady field with a certain intensity and also various constraints such as the need to provide a suitable location for rats within the supplier. Considering the current of generator and long term use of it during the day, a fan installed at the top of it was used to prevent heating and appropriate ventilation of system. Generating device generally consists of two coils in opposite direction, and 50 HZ alternating current was used to generate electromagnetic field.
Dissection and sampling:
At first, rats were anesthetized with cotton which was soaked in chloroform in a closed plastic container and the abdominal skin along the midline was incised by scissors and forceps, then rat's heart tissue were separated by scissors and it is divided for producing specimens for light microscopy. Specimens were placed into 10% buffered formalin and various stages of sections preparation were performed along with by H&E, and three chrome staining. After preparation of tissue blocks, sections (to a thickness of 6 microns) were prepared by micro tom device. Then, sections were placed in a warm bath to be smooth. Then, the slides which had been inoculated previously with alumina glue were placed below the sections which were on the surface and middle of the slides.
For evaluating and comparing the results of the control and test groups ANOVA statistical test was used.
In heart tissue of control group, all cell lines and heart tissue thickness were normal. Light photomicrograph of left ventricle of the heart muscle tissue in control group has been shown; as you see, all layers of muscle cells in this section are normal (Fig.1) and we do not see any abnormality in nucleus or cytoplasm (Fig.2).But in test group, tissue organization is so severely overcrowded, nuclei of muscular cells have been polymorphic and the spaces created around the nucleus and cytoplasm are paled (Fig.3); and tissue fibrosis, cell coagulative necrosis and hemorrhage have been observed (Fig.4).In muscular cell of heart nucleus, swelling and degenerative changes are seen as vacualation of cytoplasm and nucleus which are associated with coagulative necrosis; moreover, some necrotic cells are currently being slippery with focal necrosis, and scattered.
[FIGURE 1 OMITTED]
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
[FIGURE 4 OMITTED]
Considering the widespread role of electromagnetic fields on human being and other living creatures, most studies had been performed on the effects of electromagnetic fields on different organs. Kopolia and Lisa have studied about effects of electromagnetic fields on brain and testicular tissues [14,17]. Tahemura et al also have investigated the effects of electromagnetic fields on testicular tissue . According to World Health Organization (WHO) report, electromagnetic waves can cause tissue damage by increasing temperature and hyperthermia of tissue . But be careful that in this study, we have used some specific techniques such as installing air conditioner in the EMF field generating device and controlling inside and outside temperature of mice container by two separate thermometers for preventing abnormal and uncontrolled rise in temperature; and these techniques hampered hyperthermia by device, therefore observed damages had been caused by tissue hyperthermia through electromagnetic waves.
In research on the 2-month rat heart during fetal and postnatal phases up to 2 months that has been exposed to electromagnetic fields with 120 gauss intensity, compared with the controls, nucleus of cardiac cells was dense and spindle, nuclei and chromatin blurred and the cell ranges weren't visible; all in all, cells and their nuclei were smaller than those of control group and intracellular vessels decreased . Other studies have shown that electromagnetic fields cause tachyarrhythmia, bradicardia, hypertension and increased myocardial infarction [29,15,4]. In the research by baran et al, it is shown that electromagnetic fields with 50HZ frequency cause blood disturbances in different parts of the body . In a survey by Saeid Babayi et al performed on the liver, a significant necrosis (non apoptotic cell death) was reported . Similarly, this type of cell death (necrosis) resulting from electromagnetic waves in other cells has been reported by Tenezzu in 2006 The results of mentioned studies are consistent with the results of this study . Research performed by Soleimani Rad et al  showed that purkinje cells would be small and dense and would have pignotic nuclei and number of cells would decrease and distances between them would be more under the effect of electromagnetic field. These changes cause irregular purkinje layer and similarly, other cells such as pyramidal cells would be observed dense, small and vacuolated . In another study by Graham et al  on the heart tissue, results indicated that cardiac cells were dense and spindle-shaped, nucleus and chromatin were vague and cells margin were not obvious, and all in all, cells and their nuclei have been decreased . In another study the effects of certain unusual gathering masses of epithelial cells were observed in gingival connective tissue that could be a sign of cell loss in these cells, it means that some of the secretary cells are voided from their original location and create certain pathological sight that is a sign of cell and tissue necrosis in gum tissue [4,14]. A survey by Kucheh Esfahani et al on heart tissue, indicate negative effects of electromagnetic fields and L-Arginine in growth and development of mouse embryo heart and positive effects of electromagnetic fields and L-Arginine in increasing the number of red blood cells and heart rate. Results of Mortazavy et al studies in the motility and number of rat sperms showed that increasing intensity of electromagnetic field has negative impact on the ability of sperm motility in rats . Keshtgar et al researches on the bone absorption, showed electromagnetic fields have negative effects on increasing bone uptake . Jasemy et all studies on sperm count and motility in rats indicate that electromagnetic fields damage spermatogenesis . Samani et al finding on heart tissue in rats showed that prolonged exposure to the electromagnetic fields have bad affect on the cardiovascular system . Also Gholam Hosseini et al results show that cytotoxic effects of lead acetate on rabbit heart tissue during the chronic phase cause obvious changes. The results of this study showed that not only the electromagnetic waves has caused coagulative necrosis, cytoplasmic vaculation, congestion of blood vessels, cell atrophy, cell loss and increased distances between the cells, but also histopathological studies showed that electromagnetic waves can cause significant changes on heart tissue (P<0.05) .
These findings indicate harmful effects of long-term exposure to electromagnetic fields on cardiac tissue that propose necessity of taking protective strategies against feasible shock. Although the current results cannot be a definitive evidence linking the radiation of non ionized rays (electromagnetic fields) with various diseases or damage to biological systems, the current study reinforces previous studies findings that warming in the tissue may play a role on programmed cell death (apoptosis). To achieve a real benchmark for the field effects on the heart tissue, more and wider studies are needed to be done in the laboratory.
This essay is a result of approved research project by the central board of scientific, literary, artistic associations of Islamic Azad University. We are grateful to all colleagues and officials for their help. Also, we are thankful to research deputy of "Islamic Azad University of Tabriz" and "Medical Faculty of Tabriz University".
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(1) Sina Shadfar, (1) Seyed Hossein Zamzam, (1) Mohammad Bafandeh Zendeh and (2) Vahid Tabatabaie
(1) Young Researchers Club, Tabriz Branch, Islamic Azad University, Tabriz, Iran
(2) Resident of large animal internal medicine, University of Shahr e Kord
Dr. Seyed Hossein Zamzam, Young Researchers Club, Tabriz Branch, Islamic Azad University, Tabriz, Iran.
E-mail: Hossein.firstname.lastname@example.org; Tel: +989144041393
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|Title Annotation:||Original Article|
|Author:||Shadfar, Sina; Zamzam, Seyed Hossein; Zendeh, Mohammad Bafandeh; Tabatabaie, Vahid|
|Publication:||Advances in Environmental Biology|
|Date:||Jun 1, 2012|
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