Static Magnetic Fields Modulate the Response of Different Oxidative Stress Markers in a Restraint Stress Model Animal.

Stress is a state of vulnerable homeostasis that alters the physiological and behavioral responses. Stress induces oxidative damage in several organs including the brain, liver, kidney, stomach, and heart. Preliminary findings suggested that the magnetic stimulation could accelerate the healing processes and has been an effective complementary therapy in different pathologies. However, the mechanism of action of static magnetic fields (SMFs) is not well understood. In this study, we demonstrated the effects of static magnetic fields (0.8 mT) in a restraint stressed animal model, focusing on changes in different markers of oxidative damage. A significant increase in the plasma levels of nitric oxide (NO), malondialdehyde (MDA), and advanced oxidation protein products (AOPP), and a decrease in superoxide dismutase (SOD), glutathione (GSH), and glycation end products (AGEs) were observed in restraint stress model. Exposure to SMFs over 5 days (30, 60, and 240 min/day) caused a decrease in the NO, MDA, AGEs, and AOPP levels; in contrast, the SOD and GSH levels increased. The response to SMFs was time-dependent. Thus, we proposed that exposure to weak-intensity SMFs could offer a complementary therapy by attenuating oxidative stress. Our results provided a new perspective in health studies, particularly in the context of oxidative stress.

Neurogenesis in the subventricular zone following transcranial magnetic field stimulation and nigrostriatal lesions.

Neurogenesis continues at least in two regions of the mammalian adult brain, the subventricular zone (SVZ) and the subgranular zone in hippocampal dentate gyrus. Neurogenesis in these regions is subjected to physiological regulation and can be modified by pharmacological and pathological events. Here we report the induction of neurogenesis in the SVZ and the differentiation after nigrostriatal pathway lesion along with transcranial magnetic field stimulation (TMFS) in adult rats. Significant numbers of proliferating cells demonstrated by bromodeoxyuridine-positive reaction colocalized with the neuronal marker NeuN were detected bilaterally in the SVZ, and several of these cells also expressed tyrosine hydroxylase. Transplanted chromaffin cells into lesioned animals also induced bilateral appearance of subependymal cells. These results show for the first time that unilateral lesion, transplant, and/or TMFS induce neurogenesis in the SVZ of rats and also that TMFS prevents the motor alterations induced by the lesion.

Effects of taurine on ozone-induced memory deficits and lipid peroxidation levels in brains of young, mature, and old rats.

To determine the antioxidant effects of taurine on changes in memory and lipid peroxidation levels in brain caused by exposure to ozone, we carried out two experiments. In the first experiment, 150 rats were separated into three experimental blocks (young, mature, and old) with five groups each and received one of the following treatments: control, taurine, ozone, taurine before ozone, and taurine after ozone. Ozone exposure was 0.7-0.8 ppm for 4 h and taurine was administered ip at 43 mg/kg, after or before ozone exposure. Subsequently, rats were tested in passive avoidance conditioning. In the second experiment, samples from frontal cortex, hippocampus, striatum, and cerebellum were obtained from 60 rats (young and old), using the same treatments with 1 ppm ozone. Results show both an impairment in short-term and long-term memory with ozone and an improvement with taurine after ozone exposure, depending on age. In contrast to young rats, old rats showed peroxidation in all control groups and an improvement in memory with taurine. When taurine was applied before ozone, we found high peroxidation levels in the frontal cortex of old rats and the hippocampus of young rats; in the striatum, peroxidation caused by ozone was blocked when taurine was applied either before or after ozone exposure.

Transplant of cultured neuron-like differentiated chromaffin cells in a Parkinson's disease patient. A preliminary report.

BACKGROUND: Treatment of Parkinson's Disease (PD) has been attempted by others by transplanting either the patient's own adrenal medullary tissue or fetal substantia nigra into caudate or putamen areas. However, the difficulties inherent in using the patient's own adrenal gland, or the difficulty in obtaining human fetal tissue, has generated the need to find alternative methods. METHODS: We report here of an alternative to both procedures by using as transplant material cultured human adrenal chromaffin cells differentiated into neuron-like cells by extremely low frequency magnetic fields (ELF MF). RESULTS: The results of this study show that human differentiated chromaffin cells can be grafted into the caudate nucleus of a PD patient, generating substantial clinical improvement, as measured by the Unified Rating Scale for PD, which correlated with glucose metabolism and D2 DA receptor increases as seen in a PET scan, while allowing a 70% decrease in L-Dopa medication. DISCUSSION: This is the first preliminary report showing that transplants of cultured differentiated neuron-like cells can be successfully used to treat a PD patient.

Neuronal differentiation of chromaffin cells in vitro, induced by extremely low frequency magnetic fields or nerve growth factor: a histological and ultrastructural comparative study.

The application of nerve growth factor (NGF) to primary adrenal medulla chromaffin cell cultures induces phenotypic changes characterized mainly by the presence of neurites. A similar effect has been seen when these cells are stimulated by extremely low frequency magnetic fields (ELFMF). In this study, newborn rat chromaffin cells were cultured and subjected to NGF or ELFMF in order to compare their histological and ultrastructural characteristics. Cells cultured in the presence of NGF developed cytoplasmic projections and their distal ends showed growth cones as well as filopodia. With scanning and transmission electron microscopy, an increased submembranous electron density was observed in the nuclei of cells as well as irregular, wavy neuritic projections with a moderate number of varicosities, as well as the prevalence of intermediate filaments among the cytoskeleton components. Cells stimulated with ELFMF presented straighter neuritic extensions with a greater number of varicosities. With the transmission electron microscope, numerous neurotubules were observed, both in the cell soma and in their neuritic extensions. In both groups, growth cones were clearly identified by their ultrastructural characteristics. The differences seen in the cytoskeleton of cells stimulated with NGF or ELFMF suggest differential stimulation mechanisms possibly determining the biochemical, electrophysiological, and morphological characteristics in both types of cell cultures.

The role of voltage-gated Ca2+ channels in neurite growth of cultured chromaffin cells induced by extremely low frequency (ELF) magnetic field stimulation.

The ion Ca2+ has been shown to play an important role in a wide variety of cellular functions, one of them being related to cell differentiation in which nerve growth factor (NGF) is involved. Chromaffin cells obtained from adrenals of 2- to 3-day-old rats were cultured for 7 days. During this time, these cells were subjected to the application of either NGF or extremely low frequency magnetic fields (ELF MF). Since this induced cell differentiation toward neuronal-like cells, the mechanism by which this occurred was studied. When the L-Ca2+ channel blocker nifedipine was applied simultaneously with ELF MF, this differentiation did not take place, but it did when an N-Ca2+ channel blocker was used. In contrast, none of the Ca2+ channel blockers prevented differentiation in the presence of NGF. In addition, Bay K-8644, an L-Ca2+ channel agonist, increased both the percentage of differentiated cells and neurite length in the presence of ELF MF. This effect was much weaker in the presence of NGF. [3H]-noradrenaline release was reduced by nifedipine, suggesting an important role for L-Ca2+ channels in neurotransmitter release. Total high voltage Ca2+ currents were significantly increased in ELF MF-treated cells with NGF, but these currents in ELF MF-treated cells were more sensitive to nifedipine. Amperometric analysis of catecholamine release revealed that the KCl-induced activity of cells stimulated to differentiate by ELF MF is highly sensitive to L-type Ca2+ channel blockers. A possible mechanism to explain the way in which the application of magnetic fields can induce differentation of chromaffin cells into neuronal-like cells is proposed.

Determination of dopamine-releasing protein (DARP) in cerebrospinal fluid of patients with neurological disorders.

Levels of DARP in the cerebrospinal fluid (CSF) of patients having a wide variety of neurological disorders were determined. Neurological disorders were categorized as degenerative, demyelinating, epilepsy, trauma, hydrocephalia, inflammatory, A-V malformation, CNS neoplasia, parasitic and stroke. DARP levels were determined by an enzyme-linked immunoabsorbent assay (ELISA) using monoclonal anti-DARP antibodies. A synthetic peptide corresponding to the first 36 aa of the N-terminal of DARP was used as standard. A total of 7 non-neurological patients and 73 patients with neurological disorders were tested. The relative concentrations of DARP decreased in patients with Parkinson's diseases vs. patients with non-neurological diseases and increased in other neuropathologies such as demyelinating, hydrocephalia and A-V malformations. Data obtained suggest that changes in the percentage and concentration of DARP may correlate with certain neurological disorders, showing particularly low levels in Parkinson's disease patients.

Rapid eye movement (REM) sleep deprivation in 6-OHDA nigro-striatal lesioned rats with and without transplants of dissociated chromaffin cells.

Since both REM sleep deprivation and unilateral 6-OHDA lesions induce supersensitivity of DA receptors, the purpose of this study was to determine whether the response of rats with such lesions would be modified by REM sleep deprivation. In addition, the effect of grafts of dissociated chromaffin cells was also tested. Rats with 6-OHDA lesions were subjected to 24 or 72 h of REM sleep deprivation and tested with various doses of apomorphine to determine turning behavior frequencies. At end of those experiments, the animals were transplanted with dissociated chromaffin cells and turning behavior was tested again. The results showed that REM sleep deprivation nearly doubled the turning behavior frequency, that chromaffin cell grafts decreased it, but that REM deprivation in grafted animals still seemed to produce an increase of post-synaptic supersensitivity independent of denervation. The results were discussed in terms of the possible relationship of sleep with Parkinson's disease through the DA system.

Delay in manifestations of aging by grafting NGF cultured chromaffin cells in adulthood.

Dopamine agonists or grafts compensate impaired motor functions in aged rats. However, there is no evidence showing whether grafting in adulthood retard aging manifestations. Motor performance of 13-month-old rats was tested on 2 meter-long wooden beams which had a 15 degree inclination and whose thickness varied from 3, 6, 12, 18, to 24 mm. Rats at 14 months were randomly assigned to 3 groups: sham graft (Group 1); intrastriatal graft of chromaffin cells cultured with NGF (Group 2); intrastriatal graft of chromaffin cells (Group 3). Motor performance was tested at monthly intervals up until rats were 26 months old. Two more groups were included: 26-month-old naive rats (Group 4); and 3- to 5-month-old naive rats (Group 5) both evaluated only once. At 26 months, the basal activity of ventral mesencephalic dopaminergic neurons was recorded. Results showed in Group 2 delay of motor detriments seen in aged rats, maintenance of basal firing rates of nigral cells compared to those of younger rats, and greater survival of substantia nigra cells. It is suggested that NGF cultured chromaffin cells produce a delay of motor detriments in aged rats, as a result of inducing survival and firing rates of nigral cells comparable to those seen in young rats.

Phenotypic changes induced by replating of early post-natal rat chromaffin cells.

Postnatal chromaffin cells from rat adrenal medulla in culture respond to NGF by expressing neuronal traits. The replating of chromaffin cells after trypsinization produced neurite growth in a manner similar to that of NGF. The combination of replating and NGF exposure did not induce phenotypic changes over and above those observed by NGF alone. The morphological changes are independent of the preliminary culture conditions. The results of this study demonstrate for the first time that simple replating of young chromaffin cells can induce neuronal traits indistinguishable from those observed with NGF.

Comparison between low frequency magnetic field stimulation and nerve growth factor treatment of cultured chromaffin cells, on neurite growth, noradrenaline release, excitable properties, and grafting in nigrostriatal lesioned rats.

Adrenal chromaffin cells in vitro respond to nerve growth factor (NGF) by expressing neuronal traits. Low frequency magnetic (LFM) field stimulation, while inducing a variety of effects on several cell types, has never been studies as to its effects on chromaffin cell cultures. The purpose of this study was to compare the effects of LFM field stimulation with that of NGF on the morphological phenotype, on noradrenaline (NA) release, and on membrane excitability of cultured chromaffin cells. We also tested the effects of grafting LFM and NGF-treated chromaffin cells into the caudate nucleus of rats with 6-hydroxydopamine lesions of the nigrostriatal pathway. The results of this study showed that LFM field stimulation produced neurite growth of cultured chromaffin cells in a manner similar to that of NGF exposure. The combination of the two procedures did not induce changes above those observed by NGF alone. Both NGF- and LFM-treated chromaffin cells released [3H]NA equally in response to a depolarizing concentration of KCl. On the other, Na+ current density of LFM field stimulation increased, but to a lesser extent than that seen in NGF-treated cells. In addition both types of cells when transplanted into nigrostriatal-lesioned animals induced a similar decrease in the motor asymmetries produced by the lesion. When NGF- or LFM-treated chromaffin cells where compared to untreated control cells, no significant differences were observed in [3H]NA release, on Na+ current densities, or on postgraft motor asymmetries. The results are discussed in terms of the fact that LFM-stimulated cells can be differentiated in a manner similar to NGF-treated cells, by acquiring sympathetic like traits which in turn can diminish motor asymmetries when grafted into nigrostriatal-lesioned rats.