Glucose administration attenuates spatial memory deficits induced by chronic low-power-density microwave exposure

Radiofrequency radiation and Alzheimer's disease: harmful and therapeutic implications

PURPOSE

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by memory loss and cognitive decline. The relationship between AD and radiofrequency (RF) radiation emitted by wireless devices remains under investigation. The aim of this review is to comprehensively explore the effects of RF radiation on AD by evaluating existing literature. This review used Web of Science, Scopus, and PubMed to find relevant studies on AD and RF radiation. This review evaluates a total of 81 studies, including animal models, human studies, and in vitro experiments, with results summarized in tables for clarity.

CONCLUSION

Some studies suggest RF aggravates AD by increasing oxidative stress, impairing blood-brain barrier integrity, and promoting amyloid-beta deposition. Conversely, other studies indicate RF may have protective benefits, such as enhancing brain mitochondrial functions and reducing amyloid-beta levels. Understanding the RF-AD relationship, including parameters like frequency and exposure time, is crucial for therapeutic strategies. The studies reviewed highlight RF radiation's dual effects on AD, underscoring the need for a detailed approach. Further studies are required to clarify these effects and inform preventive and therapeutic measures.

Changes in the excitability of primary hippocampal neurons following exposure to 3.0 GHz radiofrequency electromagnetic fields

Exposures to radiofrequency electromagnetic fields (RF-EMFs, 100 kHz to 6 GHz) have been associated with both positive and negative effects on cognitive behavior. To elucidate the mechanism of RF-EMF interaction, a few studies have examined its impact on neuronal activity and synaptic plasticity. However, there is still a need for additional basic research that further our understanding of the underlying mechanisms of RF-EMFs on the neuronal system. The present study investigated changes in neuronal activity and synaptic transmission following a 60-min exposure to 3.0 GHz RF-EMF at a low dose (specific absorption rate (SAR) < 1 W/kg). We showed that RF-EMF exposure decreased the amplitude of action potential (AP), depolarized neuronal resting membrane potential (MP), and increased neuronal excitability and synaptic transmission in cultured primary hippocampal neurons (PHNs). The results show that RF-EMF exposure can alter neuronal activity and highlight that more investigations should be performed to fully explore the RF-EMF effects and mechanisms.

Nasal Delivery of Cinnarizine Thermo- and Ion-Sensitive In Situ Hydrogels for Treatment of Microwave-Induced Brain Injury

(1) Background: When the body is exposed to microwave radiation, the brain is more susceptible to damage than other organs. However, few effective drugs are available for the treatment of microwave-induced brain injury (MIBI) because most drugs are difficult to cross the blood–brain barrier (BBB) to reach the brain. (2) Methods: Nasal cinnarizine inclusion complexes with thermo-and ion-sensitive hydrogels (cinnarizine ISGs) were prepared to treat MIBI and the characteristics of the inclusion complexes and their thermo-and ion-sensitive hydrogels were evaluated. (3) Results: Due to high viscosity, cinnarizine ISGs can achieve long-term retention in the nasal cavity to achieve a sustained release effect. Compared with the model, the intranasal thermo-and ion-sensitive cinnarizine ISGs significantly improved the microwave-induced spatial memory and spontaneous exploration behavior with Morris water maze and open field tests. Cinnarizine ISGs inhibited the expression of calcineurin and calpain 1 in the brain, which may be related to the inhibition of calcium overload by cinnarizine. (4) Conclusion: Intranasal thermo- and ion-sensitive cinnarizine ISGs are a promising brain-targeted pharmaceutical preparation against MIBI.

Influences of exposure to 915-MHz radiofrequency identification signals on serotonin metabolites in rats: a pilot study

PURPOSE

The influences of radiofrequency electromagnetic exposure on animal health, particularly on serotonin metabolism, are not well-elucidated. In this in vivo study, we studied the influences of exposure to radiofrequency identification (RFID) signals on serotonin metabolism.

MATERIALS AND METHODS

Twenty-two male Sprague-Dawley rats were assigned to sham (n = 10) and RFID-exposed (n = 12) groups. Rats in the RFID-exposed group were exposed to RFID signals at an average whole-body specific absorption rate of 2 W/kg for 8 h/day, 5 days/week for 2 weeks. Before and after RFID exposure, 24-h urine was collected from each rat. Urinary tryptophan, 5-hydroxytryptophan, serotonin, 5-hydroxyindoleacetic acid, and 5-methoxyindole-3-acetic acid concentrations were examined using gas chromatography-mass spectrometry, and changes in the patterns of values were compared between the two groups.

RESULTS

Urinary levels of serotonin decreased by 20% (p = .041, Student's t-test) and 40% (p = .024, Student's t-test) in both the sham and RFID-exposed groups, respectively. The level of 5-methoxyindole-3-acetic acid decreased by 30% in the RFID-exposed group (p = .039, Student's t-test).

CONCLUSION

Our results indicate that exposure to RFID signals at a specific absorption rate of 2 W/kg is sufficient to alter serotonin metabolism in rats regardless of whether the exposure level is considered biohazardous.

The radio-protective effect of rosmarinic acid against mobile phone and Wi-Fi radiation-induced oxidative stress in the brains of rats

BACKGROUND

Rosmarinus officinalis L. is an aromatic perennial herb from which rosmarinic acid (RA) can be extracted. This research was conducted to assess the effectiveness of RA against radio frequency (RF) radiation-induced oxidative stress due to 915 MHz (mobile phone) and 2450 MHz (Wi-Fi) frequencies in rats.

METHODS

The animals were separated into six groups, including group 1 receiving normal saline (NS), group 2 (NS/Wi-Fi) and group 4 (NS/mobile), which received NS plus 60 min/day of exposure to the electromagnetic radiation (EMR) for 1 month, group 3 (RA/Wi-Fi) and group 5 (RA/mobile) received RA (20 mg/kg/day, po) plus 60 min/day of EMR, and group 6 (RA) received only RA.

RESULTS

There was a significant elevation of protein carbonylation (PC), nitric oxide (NO) and malondialdehyde (MDA) and significant reduction in glutathione (GSH), glutathione peroxidase (GPx), total antioxidant capacity (TAC), superoxide dismutase (SOD) and catalase (CAT) in the RF radiation-exposed rats' brain compared to the control group. RA reduced the levels of NO, PC and MDA and it also elevated the TAC, GPx, SOD, CAT and GSH levels in the rats' brains in the RA/Wi-Fi and RA/mobile groups compared to the NS/Wi-Fi and NS/mobile groups, respectively.

CONCLUSION

It can be concluded that RA can be considered a useful candidate for protecting brain tissues against RF radiation-induced oxidative stress at 915 and 2450 MHz frequencies through ameliorative effects on the antioxidant enzyme activities and oxidative stress indices.

Machine learning-based identification of radiofrequency electromagnetic radiation (RF-EMR) effect on brain morphology: a preliminary study

The brain of a human and other organisms is affected by the electromagnetic field (EMF) radiations, emanating from the cell phones and mobile towers. Prolonged exposure to EMF radiations may cause neurological changes in the brain, which in turn may bring chemical as well as morphological changes in the brain. Conventionally, the identification of EMF radiation effect on the brain is performed using cellular-level analysis. In the present work, an automatic image processing-based approach is used where geometric features extracted from the segmented brain region has been analyzed for identifying the effect of EMF radiation on the morphology of a brain, using drosophila as a specimen. Genetic algorithm-based evolutionary feature selection algorithm has been used to select an optimal set of geometrical features, which, when fed to the machine learning classifiers, result in their optimal performance. The best classification accuracy has been obtained with the neural network with an optimally selected subset of geometrical features. A statistical test has also been performed to prove that the increase in the performance of classifier post-feature selection is statistically significant. This machine learning-based study indicates that there exists discrimination between the microscopic brain images of the EMF-exposed drosophila and non-exposed drosophila. Graphical abstract Proposed Methodology for identification of radiofrequency electromagnetic radiation (RF-EMR) effect on the morphology of brain of Drosophila.

Intranasal tetrandrine temperature-sensitive in situ hydrogels for the treatment of microwave-induced brain injury

The brain is the most sensitive organ to microwave radiation. However, few effective drugs are available for the treatment of microwave-induced brain injury due to the poor drug permeation into the brain. Here, intranasal tetrandrine (TET) temperature-sensitive in situ hydrogels (ISGs) were prepared with poloxamers 407 and 188. Its characteristics were evaluated, including rheological properties, drug release in vitro, and mucosal irritation. The pharmacodynamics and brain-targeting effects were also studied. The highly viscous ISGs remained in the nasal cavity for a long time with the sustained release of TET and no obvious ciliary toxicity. Intranasal temperature-sensitive TET ISGs markedly improved the spatial memory and spontaneous exploratory behavior induced by microwave with the Morris water maze (MWM) and the open field test (OFT) compared to the model. The ISGs alleviated the microwave-induced brain damage and inhibited the certain mRNA expressions of calcium channels in the brain. Intranasal temperature-sensitive TET ISGs was rapidly absorbed with a shorter T_max (4.8 h) compared to that of oral TET (8.4 h). The brain targeting index of intranasal temperature-sensitive TET ISGs was as 2.26 times as that of the oral TET. Intranasal temperature-sensitive TET ISGs are a promising brain-targeted medication for the treatment of microwave-induced brain injury.

Effect of electromagnetic radiation on redox status, acetylcholine esterase activity and cellular damage contributing to the diminution of the brain working memory in rats

Behavioral impairments are the most pragmatic outcome of long-term mobile uses but the underlying causes are still poorly understood. Therefore, the Aim of the present study to determine the possible mechanism of mobile induced behavioral alterations by observing redox status, cholinesterase activity, cellular, genotoxic damage and cognitive alterations in rat hippocampus. This study was carried out on 24 male Wistar rats, randomly divided into four groups (n = 6 in each group): group I consisted of sham-exposed (control) rats, group II-IV consisted of rats exposed to microwave radiation (900 MHz) at different time duration 1 h, 2 h, and 4 h respectively for 90 days. After 90 days of exposure, rats were assessing learning ability by using T-Maze. A significantly increased level of malondialdehyde (MDA) with concomitantly depleted levels of superoxide dismutase (SOD), catalase (CAT) and redox enzymes (GSH, GPX, GR, GST, G-6PDH) indicated an exposure of mobile emitted EMR induced oxidative stress by the depleted redox status of brain cells. The depletion in the acetylcholinesterase (AChE) level reveals altered neurotransmission in brain cells. Resultant cellular degeneration was also observed in the radiation-exposed hippocampus. Conclusively, the present study revealed that microwave radiation induces oxidative stress, depleted redox status, and causes DNA damage with the subsequent reduction in working memory in a time-dependent manner. This study provides insight over the associative reciprocity between redox status, cellular degeneration and reduced cholinergic activity, which presumably leads to the behavioral alterations following mobile emitted electromagnetic radiation.

Can Low-Level Exposure to Radiofrequency Fields Effect Cognitive Behaviour in Laboratory Animals? A Systematic Review of the Literature Related to Spatial Learning and Place Memory

This review considers whether exposure to low-level radiofrequency (RF) fields, mostly associated with mobile phone technology, can influence cognitive behaviour of laboratory animals. Studies were nominated for inclusion using an a priori defined protocol with preselected criteria, and studies were excluded from analysis if they did not include sufficient details about the exposure, dosimetry or experimental protocol, or if they lacked a sham-exposed group. Overall, 62 studies were identified that have investigated the effects of RF fields on spatial memory and place learning and have been published since 1993. Of these, 17 studies were excluded, 20 studies reported no significant field-related effects, 21 studies reported significant impairments or deficits, and four studies reported beneficial consequences. The data do not suggest whether these outcomes are related to specific differences in exposure or testing conditions, or simply represent chance. However, some studies have suggested possible molecular mechanisms for the observed effects, but none of these has been substantiated through independent replication. Further behavioural studies could prove useful to resolve this situation, and it is suggested that these studies should use a consistent animal model with standardized exposure and testing protocols, and with detailed dosimetry provided by heterogeneous, anatomically-realistic animal models.

Effects of repeated restraint stress and WiFi signal exposure on behavior and oxidative stress in rats

Today, due to technology development and aversive events of daily life, Human exposure to both radiofrequency and stress is unavoidable. This study investigated the co-exposure to repeated restraint stress and WiFi signal on cognitive function and oxidative stress in brain of male rats. Animals were divided into four groups: Control, WiFi-exposed, restrained and both WiFi-exposed and restrained groups. Each of WiFi exposure and restraint stress occurred 2 h (h)/day during 20 days. Subsequently, various tests were carried out for each group, such as anxiety in elevated plus maze, spatial learning abilities in the water maze, cerebral oxidative stress response and cholinesterase activity in brain and serum. Results showed that WiFi exposure and restraint stress, alone and especially if combined, induced an anxiety-like behavior without impairing spatial learning and memory abilities in rats. At cerebral level, we found an oxidative stress response triggered by WiFi and restraint, per se and especially when combined as well as WiFi-induced increase in acetylcholinesterase activity. Our results reveal that there is an impact of WiFi signal and restraint stress on the brain and cognitive processes especially in elevated plus maze task. In contrast, there are no synergistic effects between WiFi signal and restraint stress on the brain.

Study on dose-dependent, frequency-dependent, and accumulative effects of 1.5 GHz and 2.856 GHz microwave on cognitive functions in Wistar rats

Many studies have revealed the cognitive decline induced by microwave radiation. However, the systematic study on dose-dependent, frequency-dependent and accumulative effects of microwave exposure at different frequencies was lacking. Here, we studied the relationship between the effects and the power and frequency of microwave and analyzed the accumulative effects of two different frequency microwaves with the same average power density. After microwave radiation, declines in spatial learning and memory and fluctuations of brain electric activities were found in the 10 mW/cm2 single frequency exposure groups and accumulative exposure groups. Meanwhile, morphological evidences in hippocampus also supported the cognitive dysfunction. Moreover, the decrease of Nissl contents in neurons indicated protein-based metabolic disorders in neurons. By detecting the key functional proteins of cholinergic transmitter metabolism, cytokines, energy metabolism and oxidative stress in the hippocampus, we found that microwave could lead to multiple metabolic disorders. Our results showed that microwave-induced cognitive decline was largely determined by its power rather than frequency. Injury effects were also found in accumulative exposure groups. We particularly concerned about the safety dose, injury effects and accumulative effects of microwaves, which might be very valuable in the future.

Long term impairment of cognitive functions and alterations of NMDAR subunits after continuous microwave exposure

OBJECTIVE

The long term effects of continuous microwave exposure cannot be ignored for the simulation of the real environment and increasing concerns about the negative cognitive effects of microwave exposure.

METHODS

In this study, 220 male Wistar rats were exposed by a 2.856GHz radiation source with the average power density of 0, 2.5, 5 and 10mW/cm² for 6min/day, 5days/week and up to 6weeks. The MWM task, the EEG analysis, the hippocampus structure observation and the western blot were applied until the 12months after microwave exposure to detect the spatial learning and memory abilities, the cortical electrical activity, changes of hippocampal structure and the NMDAR subunits expressions.

RESULTS

Results found that the rats in the 10mW/cm² group showed the decline of spatial learning and memory abilities and EEG disorders (the decrease of EEG frequencies, and increase of EEG amplitudes and delta wave powers). Moreover, changes of basic structure and ultrastructure of hippocampus also found in the 10 and 5mW/cm² groups. The decrease of NR 2A, 2B and p-NR2B might contribute to the impairment of cognitive functions.

CONCLUSIONS

Our findings suggested that the continuous microwave exposure could cause the dose-dependent long term impairment of spatial learning and memory, the abnormalities of EEG and the hippocampal structure injuries. The decrease of NMDAR key subunits and phosphorylation of NR 2B might contribute to the cognitive impairment.

Microwaves and Alzheimer's disease

Alzheimer's diseases (AD) is the most common type of dementia and a neurodegenerative disease that occurs when the nerve cells in the brain die. The cause and treatment of AD remain unknown. However, AD is a disease that affects the brain, an organ that controls behavior. Accordingly, anything that can interact with the brain may affect this organ positively or negatively, thereby protecting or encouraging AD. In this regard, modern life encompasses microwaves for all issues including industrial, communications, medical and domestic tenders, and among all applications, the cell phone wave, which directly exposes the brain, continues to be the most used. Evidence suggests that microwaves may produce various biological effects on the central nervous system (CNS) and many arguments relay the possibility that microwaves may be involved in the pathophysiology of CNS disease, including AD. By contrast, previous studies have reported some beneficial cognitive effects and that microwaves may protect against cognitive impairment in AD. However, although many of the beneficial effects of microwaves are derived from animal models, but can easily be extrapolated to humans, whether microwaves cause AD is an important issue that is to be addressed in the current review.

Effects of fetal microwave radiation exposure on offspring behavior in mice

The recent rapid development of electronic communication techniques is resulting in a marked increase in exposure of humans to electromagnetic fields (EMFs). This has raised public concerns about the health hazards of long-term environmental EMF exposure for fetuses and children. Some studies have suggested EMF exposure in children could induce nervous system disorders. However, gender-dependent effects of microwave radiation exposure on cognitive dysfunction have not previously been reported. Here we investigated whether in utero exposure to 9.417-GHz microwave throughout gestation (Days 3.5-18) affected behavior, using the open field test (OFT), elevated-plus maze (EPM), tail suspension test (TST), forced swimming test (FST) and Morris water maze (MWM). We found that mice showed less movement in the center of an open field (using the OFT) and in an open arm (using the EPM) after in utero exposure to 9.417-GHz radiation, which suggested that the mice had increased anxiety-related behavior. Mice demonstrated reduced immobility in TST and FST after in utero exposure to 9.417-GHz radiation, which suggested that the mice had decreased depression-related behavior. From the MWM test, we observed that male offspring demonstrated decreased learning and memory, while females were not affected in learning and memory, which suggested that microwaves had gender-dependent effects. In summary, we have provided the first experimental evidence of microwaves inducing gender-dependent effects.

Spatial memory impairment is associated with hippocampal insulin signals in ovariectomized rats

Estrogen influences memory formation and insulin sensitivity. Meanwhile, glucose utilization directly affects learning and memory, which are modulated by insulin signals. Therefore, this study investigated whether or not the effect of estrogen on memory is associated with the regulatory effect of this hormone on glucose metabolism. The relative expression of estrogen receptor β (ERβ) and glucose transporter type 4 (GLUT4) in the hippocampus of rats were evaluated by western blot. Insulin level was assessed by ELISA and quantitative RT-PCR, and spatial memory was tested by the Morris water maze. Glucose utilization in the hippocampus was measured by 2-NBDG uptake analysis. Results showed that ovariectomy impaired the spatial memory of rats. These impairments are similar as the female rats treated with the ERβ antagonist tamoxifen (TAM). Estrogen blockade by ovariectomy or TAM treatment obviously decreased glucose utilization. This phenomenon was accompanied by decreased insulin level and GLUT4 expression in the hippocampus. The female rats were neutralized with hippocampal insulin with insulin antibody, which also impaired memory and local glucose consumption. These results indicated that estrogen blockade impaired the spatial memory of the female rats. The mechanisms by which estrogen blockade impaired memory partially contributed to the decline in hippocampal insulin signals, which diminished glucose consumption.

Spatial memory and learning performance and its relationship to protein synthesis of Swiss albino mice exposed to 10 GHz microwaves

PURPOSE

To study the possible role of microwave (MW) exposure on spatial memory of Swiss albino mice and its relationship to protein concentration in whole brain.

MATERIALS AND METHODS

Mice were exposed to 10 GHz (Giga Hertz) microwaves with the power density of 0.25 mW/cm(2) (milliwatt per centimeter square) with average whole body specific absorption rate (SAR) 0.1790 W/kg daily for 2 hours per day (h/day) for 30 days. After exposure mice were tested for spatial memory performance using Morris water maze test (MWT). For this purpose mice (6-8 weeks old) were divided into two groups: (i) Sham exposed, and (ii) microwaves exposed. After initial training for two days, MWT was performed for another 6 days. Protein was estimated 48 h after exposure and immediately after completion of MWT.

RESULTS

Both sham-exposed and microwaves-exposed animals showed a significant decrease in escape time with training. Microwaves-exposed animals had statistically significant higher mean latency to reach the target quadrant compared to sham exposed. A concurrent decrease in protein levels was estimated in whole brain of the exposed mice compared to sham-exposed mice.

CONCLUSIONS

It can be concluded from the current study that exposure to microwave radiation caused decrements in the ability of mice to learn the special memory task, this may be due to simultaneous decrease in protein levels in the brain of mice.