M. L. Picazo

Long-Term Effects of ELF Magnetic Fields on the Mouse Testis and Serum Testosterone Levels

Male OF1 mice were exposed continuously to a magnetic field of 50 Hz and 15 μT (rms) in order to elucidate the possible alterations in testis histology and its endocrine function caused by this exposure. Mothers were chronically exposed from the age of 6 weeks and had their offspring under the same experimental conditions. Offspring were sacrificed at the age of 10 weeks and the testes were removed and studied histologically. Serum testosterone levels were measured by enzymatic immunoassay. A significant increase in the size and weight of the testes, not related to the increment of the body weight (gonadosomatic index increased), was found in the experimental group compared to the control group. Histologically, this finding is due to an increase in the interstitial tissue, associated with increased levels of testosterone in the blood. Complete spermatogenesis was found in all the animals, in both the control and experimental groups. No differences were found in the morphology of the seminiferous epithelium.

Effects of ELF Magnetic Fields on Hematological Parameters: An Experimental Model

An experimental model has been developed in which mice were chronically exposed to an ELF magnetic field, under controlled conditions, with the purpose of learning its effects on peripheral blood. The OF1 mice were continuously subjected for two generations to an external magnetic field of 15 μT (rms) and 50 Hz sinusoidal waves generated by a system of Helmholtz coils designed by our Institute (BIASC). The first generation of animals was exposed for a period of 17 weeks and the second generation, born in the field, was exposed for 14 weeks. The most usual hematological parameters of mothers (12 control and 12 exposed) and daughters (30 control and 30 exposed) were analyzed. A leukopenia in exposed daughters and significant variations of platelet levels between both experimental groups were noted. Besides a slight decrease in hematocrit, red blood cell levels and hemoglobin concentration have been observed in exposed mice. The greatest changes were found in animals of the second generation.

An Introduction to the Study of ELF Magnetic Field Effects on White Blood Cells in Mice

The purpose of this work was to initiate a study of extremely low-frequency magnetic field effects on peripheral blood in mice. Female OF1 outbred mice resistant to spontaneous tumors were introduced into an experimental magnetic field of a 0.1 mT 50 Hz sinusoidal wave generated by a source in a solenoid, for 3 months. As a consequence of physical agents, a significant leukopenia and significant qualitative alterations of white blood cells (blast cells and young lymphocytes increased) were detected in all exposed specimens. This pathology is identified as lymphocytic aleukemic leukemia.

Changes in Mouse Adrenal Gland Functionality Under Second-Generation Chronic Exposure to Elf Magnetic Fields. I. Males

The second generation of male OF1 mice chronically exposed to a magnetic field of 50 Hz and 15 µT were studied to elucidate the possible histological and endocrinological alterations in adrenal gland caused by this exposure. Animals were sacrificed at the age of 10 weeks. Cortisol plasma concentrations were determined by fluorescence polarization immunoassay, and adrenal glands were studied by histopathological methods. The body weight of the exposed animals was found to be significantly increased. Cortisol plasma concentration and adrenal cortex thickness lost the daily rhythmicity. The statistical histopathological study showed no differences in exposed versus control animals. However, 15–20% of the experimental mice present nodular cortical hyperplasia with hypertrophy, increase in dark cells, and islets of cells with large lipid vacuoles. At the ultrastructural level, a dramatic decrease in lipid content and increase in mitochondria and SER compartment and in the nuclear and nucleolar volumes were fou...

Inhibition of Melatonin in the Plasma of Third-Generation Male Mice under the Action of ELF Magnetic Fields

The pineal gland has been considered a magnetic receptor organ that regulates circadian rhythms by means of the secretion of melatonin, a potent oncostatic agent that prevents the initiation and promotion of cancer. ELF electromagnetic radiation, similar to that generated by power lines, can alter melatonin plasma levels.To study this effect, 4 OF1 mice generations have been reared subjected to a lifelong 15 μT, 50 Hz magnetic field action. This magnetic field was generated inside a Helmholtz coil system. The concentration of melatonin in the blood has been determined on 40 male mice of the third generation by means of RIA, as they reached sexual maturity (3 months).A radical decrease, more remarkable at night, of the melatonin plasma levels and the loss of the night-day secretion rhythm was observed in the experimental group. These results could be the consequence of the applied magnetic field cumulative effect. The secretion rhythms of other hormones, at the level of the hypothalamic-hypophyseal axis, m...

Interactions of ELF Magnetic Fields with Mouse Skeletal Muscle

The second generation of female OF1 mice exposed chronically to a magnetic field of 50 Hz and 15 μT (rms) was studied to find out the possible alterations in the skeletal muscle caused by this exposure. Animals were sacrificed at the age of 14 weeks, and their skeletal muscle studied by spectrophotometric and histopathological techniques. Calcium concentration was found to be significantly decreased in the experimental animals, while H2O content, Na, K, Fe, Ni, Mg, and Zn concentrations were not significantly different from those of control animals. Histologically, we found variation in fiber size, rounded and widely separated fibers, centrally located nuclei, and intermyofibrillar lipids. We could not find necrosis, inflammatory infiltrate, or loss of either the filaments or the cross-striation.

Histopathology of the Harderian gland of rodents exposed to ELF magnetic fields

Abstract The Harderian gland is a possible magnetosensitive organ. The aim of this study was to look at the possible effects on the Harderian gland of mice after exposure to an artificial magnetic field. Sixty 0F1 three-month old female mice were selected for this study. The mice were exposed continuously to an artificial magnetic field of 1 G (10 −4 T) and 50 Hz during a three-month period. The effects were evaluated histologically. The results show, only in the experimental group, non-reversible histopathological lesions with anaplasic foci in 26% of Harderian glands. These lesions also include in situ development of adenocarcinomas. Confidence intervals applied to the statistical studies show 95% and 99% (14.75–41.13 and 11.54–45.72, respectively).

ELF Magnetic Fields and Protein Changes in Mouse Skeletal Muscle

The second generation of female OF1 mice exposed chronically to an ELF field of 50 Hz and 15 μT (rms), generated in a Helmholtz coil system, was studied to determine the possible protein changes in the skeletal muscle associated with this exposure. Animals were sacrificed at the age of 14 weeks, and their quadriceps skeletal muscles were studied by electron microscope immunocytochemistry to detect the possible changes in different proteins. Actin, myosin, desmin, and vimentin immunolabeling was found to be similar in both control (unexposed) and experimental (exposed) animals. Dystrophin was found to increase in the sarcoplasmic reticulum in the exposed animals with respect to the control ones. α-Actinin was found to increase in some damaged Z-bands of the experimental animals; troponin and calmodulin increased all along the sarcomere of the muscles of the exposed mice, whereas titin and nebulin immunoreactions decreased in the sarcomeres of the experimental group. The observed changes in these proteins s...

A HEMATOLOGICAL STUDY IN MICE FOR EVALUATION OF LEUKEMOGENESIS BY EXTREMELY LOW FREQUENCY MAGNETIC FIELDS

OF1 mice were chronically exposed to a 50-Hz sinusoidal East–West magnetic field of 15 μT (rms), in order to make a peripheral blood study for a leukemogenic evaluation of this non-ionizing radiation. Mating and pregnancy of ancestors (first generation), and birth, lactation, and development of second-generation female mice until adulthood occurred in the experimental field. A hematological study of both control and exposed 14- to 15-week-old and 50- to 52-week-old, second-generation females was realized. Individual diagnosis of specimens and statistical analysis of results revealed a high incidence of blood leukoproliferative disorders in 14- to 15-week-old exposed females (relative risk [RR] = 3.00, p = 0.0033), despite the resistance of this strain of mice to developing malignancies under normal environmental conditions before they are 26 weeks old. Especially elevated incidences of lymphocytic (RR = 6.50, p = 0.0021) and chronic (RR = 4.00, p = 0.0153) leukemias were associated with medium-term (14–15 weeks) exposure. After 50–52 weeks of exposure, the mortality of exposed mice was 30% versus 0% of control mice. From dead exposed females, 67% revealed some type of malignancy. Corresponding RR for blood leukoproliferative disorders of those exposed which survived was 2.57 (p = 0.0351). Especially important was the proportion of chronic leukemias after long-term (50–52 weeks) exposure (RR = 8.57, p = 0.0118). Moreover, a statistically nonsignificant increase of lymphoblastic–myeloblastic leukemias pointed to a relation between age of specimen and type of alteration. We suggest that the increase in blood leukemias in OF1 mice agrees with the results of numerous epidemiological studies.

Bone Density Changes in Mouse Offspring after 50-HZ, 15-μT Electromagnetic Field Long-Term Exposure of two Generations

Possible mass and bone density alterations were studied in second-generation OF1 mice exposed chronically since birth to a magnetic field of 50 Hz and 15 μT. For that purpose, 120 animals were sacrificed at the age of 12 weeks (males) and 14 weeks (females) and their femurs studied by bone densitometry. A total of 24 parameters in two groups (densitometric parameters such as total mass, total density, etc. and mechanical parameters like periosteal and endosteal circumferences, etc.) were analyzed. Statistical study showed no significant differences in exposed versus control animals. However, we observed slight alterations in some parameters such as total density, total and trabecular area, etc. that showed quantitative alterations making sexual dimorphism decrease or disappear. In other