Dose-dependent Cardiac Dysfunction and Structural Damage in Rats after Shortwave Radiation

OBJECTIVE

To detect the effects of shortwave radiation on dose-dependent cardiac structure and function in rats after radiation and to elucidate the mechanism of shortwave radiation induced cardiac injury to identify sensitive indicators and prophylactic treatment.

METHODS

One hundred Wistar rats were either exposed to 27 MHz continuous shortwave at a power density of 5, 10, and 30 mW/cm ² for 6 min or undergone sham exposure for the control (the rats had to be placed in the exposure system with the same schedules as the exposed animals, but with an inactive antenna). The Ca ²⁺, glutamic oxaloacetic transaminase (AST), creatine kinase (CK) and lactate dehydrogenase (LDH) content in the peripheral serum of the rats were detected by an automatic blood biochemical analyser. The electrocardiogram (ECG) of standard lead II was recorded by a multi-channel physiological recording and analysis system. The cardiac structure of rats was observed by light and electron microscopy.

RESULTS

The results showed that the 5, 10, and 30 mW/cm ² shortwave radiation caused a significant increased in the levels of Ca ²⁺, AST, CK, and LDH in the peripheral serum of rats. The cardiac structure was damaged by radiation and showed a disordered arrangement of myocardial fibres, the cavitation and swelling of myocardial mitochondria. These injuries were most significant 7 d after radiation and were not restored until 28 d after radiation.

CONCLUSION

Shortwave radiation of 5, 10, and 30 mW/cm ² can damage rat cardiac function, including damage to the tissue structure and ultrastructure, especially at the level of the myocardial fibres and mitochondria. Shortwave radiation at 5, 10, and 30 mW/cm ² induced damage to rat heart function and structure with a dose-effect relationship, i.e., the greater the radiation dose was, the more significant the damage was.

Exposure Effects of Terahertz Waves on Primary Neurons and Neuron-like Cells Under Nonthermal Conditions

OBJECTIVE

This study aimed to explore the potential effects of terahertz (THz) waves on primary cultured neurons from 4 rat brain regions (hippocampus, cerebral cortex, cerebellum, and brainstem) and 3 kinds of neuron-like cells (MN9D, PC12, and HT22 cells) under nonthermal conditions.

METHODS

THz waves with an output power of 50 (0.16 THz) and 10 (0.17 THz) mW with exposure times of 6 and 60 min were used in this study. Analysis of temperature change, neurite growth, cell membrane roughness, micromorphology, neurotransmitters and synaptic-related proteins (SYN and PSD95) was used to evaluate the potential effects.

RESULTS

Temperature increase caused by the THz wave was negligible. THz waves induced significant neurotransmitter changes in primary hippocampal, cerebellar, and brainstem neurons and in MN9D and PC12 cells. THz wave downregulated SYN expression in primary hippocampal neurons and downregulated PSD95 expression in primary cortical neurons.

CONCLUSION

Different types of cells responded differently after THz wave exposure, and primary hippocampal and cortical neurons and MN9D cells were relatively sensitive to the THz waves. The biological effects were positively correlated with the exposure time of the THz waves.

Behavioral Abnormality along with NMDAR-related CREB Suppression in Rat Hippocampus after Shortwave Exposure

OBJECTIVE

To estimate the detrimental effects of shortwave exposure on rat hippocampal structure and function and explore the underlying mechanisms.

METHODS

One hundred Wistar rats were randomly divided into four groups (25 rats per group) and exposed to 27 MHz continuous shortwave at a power density of 5, 10, or 30 mW/cm2 for 6 min once only or underwent sham exposure for the control. The spatial learning and memory, electroencephalogram (EEG), hippocampal structure and Nissl bodies were analysed. Furthermore, the expressions of N-methyl-D-aspartate receptor (NMDAR) subunits (NR1, NR2A, and NR2B), cAMP responsive element-binding protein (CREB) and phosphorylated CREB (p-CREB) in hippocampal tissue were analysed on 1, 7, and 14 days after exposure.

RESULTS

The rats in the 10 and 30 mW/cm2 groups had poor learning and memory, disrupted EEG oscillations, and injured hippocampal structures, including hippocampal neurons degeneration, mitochondria cavitation and blood capillaries swelling. The Nissl body content was also reduced in the exposure groups. Moreover, the hippocampal tissue in the 30 mW/cm2 group had increased expressions of NR2A and NR2B and decreased levels of CREB and p-CREB.

CONCLUSION

Shortwave exposure (27 MHz, with an average power density of 10 and 30 mW/cm2) impaired rats' spatial learning and memory and caused a series of dose-dependent pathophysiological changes. Moreover, NMDAR-related CREB pathway suppression might be involved in shortwave-induced structural and functional impairments in the rat hippocampus.

Real-time Microwave Exposure Induces Calcium Efflux in Primary Hippocampal Neurons and Primary Cardiomyocytes

OBJECTIVE

To detect the effects of microwave on calcium levels in primary hippocampal neurons and primary cardiomyocytes by the real-time microwave exposure combined with laser scanning confocal microscopy.

METHODS

The primary hippocampal neurons and primary cardiomyocytes were cultured and labeled with probes, including Fluo-4 AM, Mag-Fluo-AM, and Rhod-2, to reflect the levels of whole calcium [Ca2+], endoplasmic reticulum calcium [Ca2+]ER, and mitochondrial calcium [Ca2+]MIT, respectively. Then, the cells were exposed to a pulsed microwave of 2.856 GHz with specific absorption rate (SAR) values of 0, 4, and 40 W/kg for 6 min to observe the changes in calcium levels.

RESULTS

The results showed that the 4 and 40 W/kg microwave radiation caused a significant decrease in the levels of [Ca2+], [Ca2+]ER, and [Ca2+]MIT in primary hippocampal neurons. In the primary cardiomyocytes, only the 40 W/kg microwave radiation caused the decrease in the levels of [Ca2+], [Ca2+]ER, and [Ca2+]MIT. Primary hippocampal neurons were more sensitive to microwave exposure than primary cardiomyocytes. The mitochondria were more sensitive to microwave exposure than the endoplasmic reticulum.

CONCLUSION

The calcium efflux was occurred during microwave exposure in primary hippocampal neurons and primary cardiomyocytes. Additionally, neurons and mitochondria were sensitive cells and organelle respectively.

Real-time Assessment of Cytosolic, Mitochondrial, and Nuclear Calcium Levels Change in Rat Pheochromocytoma Cells during Pulsed Microwave Exposure Using a Genetically Encoded Calcium Indicator

Little information is available about the effects of exposure to pulsed microwaves on neuronal Ca2+ signaling under non-thermal conditions. In this study, rat pheochromocytoma (PC12) cells were exposed to pulsed microwaves for 6 min at a specific absorption rate (SAR) of 4 W/kg to assess possible real-time effects. During microwave exposure, free calcium dynamics in the cytosol, mitochondria, and nucleus of cells were monitored by time-lapse microfluorimetry using a genetically encoded calcium indicator (ratiometric-pericam, ratiometric-pericam-mt, and ratiometric-pericam-nu). We established a waveguide-based real-time microwave exposure system under accurately controlled environmental and dosimetric conditions and found no significant changes in the cytosolic, mitochondrial, or nuclear calcium levels in PC12 cells. These findings suggest that no dynamic changes occurred in [Ca2+]c, [Ca2+]m, or [Ca2+]n of PC12 cells at the non-thermal level.

Microwave-induced Apoptosis and Cytotoxicity of NK Cells through ERK1/2 Signaling

OBJECTIVE

To investigate microwave-induced morphological and functional injury of natural killer (NK) cells and uncover their mechanisms.

METHODS

NK-92 cells were exposed to 10, 30, and 50 mW/cm2 microwaves for 5 min. Ultrastructural changes, cellular apoptosis and cell cycle regulation were detected at 1 h and 24 h after exposure. Cytotoxic activity was assayed at 1 h after exposure, while perforin and NKG2D expression were detected at 1 h, 6 h, and 12 h after exposure. To clarify the mechanisms, phosphorylated ERK (p-ERK) was detected at 1 h after exposure. Moreover, microwave-induced cellular apoptosis and cell cycle regulation were analyzed after blockade of ERK signaling by using U0126.

RESULTS

Microwave-induced morphological and ultrastructural injury, dose-dependent apoptosis (P < 0.001) and cell cycle arrest (P < 0.001) were detected at 1 h after microwave exposure. Moreover, significant apoptosis was still detected at 24 h after 50 mW/cm2 microwave exposure (P < 0.01). In the 30 mW/cm2 microwave exposure model, microwaves impaired the cytotoxic activity of NK-92 cells at 1 h and down regulated perforin protein both at 1 h and 6 h after exposure (P < 0.05). Furthermore, p-ERK was down regulated at 1 h after exposure (P < 0.05), while ERK blockade significantly promoted microwave-induced apoptosis (P < 0.05) and downregulation of perforin (P < 0.01).

CONCLUSION

Microwave dose-dependently induced morphological and functional injury in NK-92 cells, possibly through ERK-mediated regulation of apoptosis and perforin expression.

Microwave exposure impairs synaptic plasticity in the rat hippocampus and PC12 cells through over-activation of the NMDA receptor signaling pathway

OBJECTIVE

The aim of this study is to investigate whether microwave exposure would affect the N-methyl-D-aspartate receptor (NMDAR) signaling pathway to establish whether this plays a role in synaptic plasticity impairment.

METHODS

48 male Wistar rats were exposed to 30 mW/cm2 microwave for 10 min every other day for three times. Hippocampal structure was observed through H&E staining and transmission electron microscope. PC12 cells were exposed to 30 mW/cm2 microwave for 5 min and the synapse morphology was visualized with scanning electron microscope and atomic force microscope. The release of amino acid neurotransmitters and calcium influx were detected. The expressions of several key NMDAR signaling molecules were evaluated.

RESULTS

Microwave exposure caused injury in rat hippocampal structure and PC12 cells, especially the structure and quantity of synapses. The ratio of glutamic acid and gamma-aminobutyric acid neurotransmitters was increased and the intracellular calcium level was elevated in PC12 cells. A significant change in NMDAR subunits (NR1, NR2A, and NR2B) and related signaling molecules (Ca2+/calmodulin-dependent kinase II gamma and phosphorylated cAMP-response element binding protein) were examined.

CONCLUSION

30 mW/cm2 microwave exposure resulted in alterations of synaptic structure, amino acid neurotransmitter release and calcium influx. NMDAR signaling molecules were closely associated with impaired synaptic plasticity.

Pathological changes in the sinoatrial node tissues of rats caused by pulsed microwave exposure

To observe microwave induced dynamic pathological changes in the sinus nodes, wistar rats were exposed to 0, 5, 10, 50 mW/cm2 microwave. In 10 and 50 mW/cm2 groups, disorganized sinoatrial node cells, cell swelling, cytoplasmic condensation, nuclear pyknosis, and anachromasis, swollen, and empty mitochondria, and blurred and focally dissolved myofibrils could be detected from 1 to 28 d, while reduced parenchymal cells, increased collagen fibers, and extracellular matrix remodeling of interstitial cells were observed from 6 to 12 months. In conclusion, 10 and 50 mW/cm2 microwave could cause structural damages in the sinoatrial node and extracellular matrix remodeling in rats.

AduoLa Fuzhenglin down-regulates microwave-induced expression of β1-adrenergic receptor and muscarinic type 2 acetylcholine receptor in myocardial cells of rats

This paper is aimed to study the effect of ADL on expression of β1-AR and M2-AchR in myocardial cells of rats exposed to microwave radiation. Immunohistochemistry, Western blot and image analysis were used to detect the expression of β1-AR and M2-AchR in myocardial cells at 7 and 14 d after microwave exposure. The results show that the expression level was higher in microwave exposure group and 0.75 g/(kg•d) ADL group than in sham operation group and significantly lower in 1.5 and 3.0 g/(kg•d) ADL groups than in microwave group. So we have a conclusion that the expression of β1-AR and M2-AchR is down-regulated in myocardial cells of rats exposed to microwave radiation. ADL can protect rats against microwave-induced heart tissue injury.

Relationship between cognition function and hippocampus structure after long-term microwave exposure

OBJECTIVE

To analyze the effects of long-term microwave exposure on hippocampal structure and function in the rat.

METHODS

Experiments were performed on 184 male Wistar rats (three exposure groups and a sham group). Microwaves were applied daily for 6 min over 1 month at average power densities of 2.5, 5, and 10 mW/cm2. Learning and memory abilities were assessed by Morris water maze. High performance liquid chromatography was used to detect neurotransmitter concentrations in the hippocampus. Hippocampal structures were observed by histopathological analysis.

RESULTS

Following long-term microwave exposure there was a significant decrease in learning and memory activity in the 7 d, 14 d, and 1 m in all three microwave exposure groups. Neurotransmitter concentrations of four amino acids (glutamate, aspartic acid, glycine, and gamma-aminobutyric acid) in hippocampus were increased in the 2.5 and 5 mW/cm2 groups and decreased in the 10 mW/cm2 group. There was evidence of neuronal degeneration and enlarged perivascular spaces in the hippocampus in the microwave exposure groups. Further, mitochondria became swollen and cristae were disordered. The rough endoplasmic reticulum exhibited sacculated distension and there was a decrease in the quantity of synaptic vesicles.

CONCLUSION

These data suggest that the hippocampus can be injured by long-term microwave exposure, which might result in impairment of cognitive function due to neurotransmitter disruption.

Treadmill exercise improved adriamycin-induced nephropathy

Adriamycin nephropathy (AN) or doxorubicin-induced chronic kidney disease (DRCKD) has several strengths as an experimental model of renal diseases involving glomerulosclerosis, tubulointerstitial inflammation and fibrosis. Exercise has shown to be beneficial to many chronic diseases. We hypothesize that treadmill exercise may improve AN, and an investigation was carried out with the AN SD rat model. Treadmill exercise was conducted three times per week, each time for 30 and 60 min. DR induced swelling of glomeruli, collagen deposition in the interstitium and renal cortex, and increased the serum levels of MDA, IL-6, PDGF-BB, MMP-2, MMP-9, TGF-beta, p-PDGFR, uric acid, serum cholesterol, triglycerides, BUN, creatinine, blood platelet count, ratio of kidney to body weight, glomerular volume, and urinary BUN and protein. Conversely, levels of serum SOD, TNF-alpha, p-PI3K, p-Akt, albumin, WBC, RBC, and urinary creatinine were decreased. Treadmill exercise ameliorated most of these damaging effects, better outcome was found for the 60-min exercise training. Conclusively, the endurance exercise is more associated with the normalization of signaling expressions involving TGF-beta, PDGF-BB, p-PDGFR, p-PI3K, and p-Akt, which may help CKD patients to restore cell survival, proliferation, and growth. As rehabilitation is a personalized medicine, an appropriate design to fit individual feasibility has to be well figured out.

Pedestrian versus motor vehicle accidents: an analysis of 5,000 patients

BACKGROUND

Pedestrian versus motor vehicle accidents are associated with substantial morbidity and mortality. Previous studies have examined pedestrian injury profiles on an individual hospital basis and have been limited by small patient populations. The objective of this study was to examine the demographics and injury profiles of pedestrian versus motor vehicle accidents in a large trauma system.

STUDY DESIGN

Five thousand pedestrians injured by motor vehicles whose records were entered in a centralized county trauma database were reviewed retrospectively over 3 years. Patients were grouped by age: pediatric (less than 15 years), adult (15 to 65 years), and elderly (older than 65 years). The main outcome measures included mortality, hospital stay, ICU stay, Injury Severity Score, Glasgow Coma Scale, Revised Trauma Score, level of residual disability, and payer source.

RESULTS

The pediatric group represented 38.1% of the study population, adults 53.9%, and the elderly 8.0%. Mortality was highest among the elderly (27.8%), followed by adults (8.1%) and children (3.1%). Overall, the pediatric group had the lowest Injury Severity Score (6.8 +/- 0.2, mean +/- SEM), the highest Revised Trauma Score (7.5 +/- 0.9), and the highest Glasgow Coma Scale (13.9+/-0.1). Hospital stay (4.9+/-0.2 days) and ICU stay (4.6 +/- 0.3 days) were also shortest in this age group. Among all patients, injuries included musculoskeletal (34.3%), head and neck (30.0%), external (24.4%), abdomen and pelvis (3.9%), chest (2.4%), spine (1.8%), and other (3.2%). Operations were required in 11%: orthopaedic (67%), thoracic (2%), abdominal (11%), neurosurgical or head (6%), and other (14%). At the time of discharge, 78% of patients had a temporary disability, 4% had a permanent handicap, and only 16% were functioning at preadmission capacity. Among those with identifiable payer sources, 45% were state or federal, 25% were cash or self-pay, 18% of patients belonged to an HMO or had a group carrier, and 12% were from other sources.

CONCLUSIONS

This study contributes the largest database reported on motor vehicle versus pedestrian accidents and finds that these accidents are common in a large urban trauma system. Hospital stay, Injury Severity Score, Revised Trauma Score, Glasgow Coma Scale, and the mortality rate worsen with age. The high mortality rate among the elderly indicates the need for more aggressive and effective prevention efforts.

Hypothermia in trauma patients

Hypothermia occurs commonly in severely injured patients and is associated with a high mortality rate. It perturbs the normal homeostatic response to injury and affects multiple organ systems and physiologic processes. In trauma patients, hypothermia-induced coagulopathy often leads to marked bleeding diathesis and frequently provides a challenge for the surgeon. Once hypothermia occurs, it is often difficult to correct. Efforts to prevent and treat hypothermia in trauma patients should be instituted in the field and continued as an integral part of the resuscitation process. Hospital personnel and physicians at various levels caring for trauma patients from the initial injury and thereafter should bear in mind that a patient's temperature is as important as any other vital sign. Appropriate measures for preventing and treating hypothermia should be instituted promptly and tended to with utmost vigilance.

Apoptosis of lymphocytes in canine peripheral blood induced by shock vibration and its mechanism

We investigated the mechanism of apoptosis induced by shock vibration in canine peripheral lymphocytes, the T-lymphocyte changes, and the expression of p53 and bax gene products related to apoptosis using the techniques of immuno- and enzyme cytochemistry. We noted obvious apoptosis after delivery of 80, 100, and 200 acceleration of gravity values (G values). The percentage of apoptotic lymphocytes was directly proportional to the G value. On the 3rd day after injury, the number of apoptotic lymphocytes reached the peak value, which was about 5 to 8 times the amount in the control group. On the contrary, on day 3 after injury, T lymphocytes decreased and were about 50% of the control group. On the other hand, we found that the percentage of p53 and bax-positive lymphocytes distinctly increased and, on the 3rd day after injury, their number was, respectively, about 2.3 and 1.8 times that in the control groups, suggesting that they may play an important role in lymphocyte apoptosis. The above-mentioned results provide an important basis for further study of the mechanism of shock-vibration injury, its prevention, and treatment.

Serotonin 5-HT1-like receptors mediate hyperactivity in rats induced by 3,4-methylenedioxymethamphetamine

This study was designed to evaluate the role of different serotonin (5-HT) receptor subtypes in mediating the effects of 3,4-methylenedioxymethamphetamine (MDMA) on rat exploration of a novel environment. The active enantiomer of MDMA, S-MDMA increases forward locomotion and suppresses investigatory behaviors and local movements. Previous studies indicate that S-MDMA-induced hyperactivity depends upon drug-induced 5-HT release. Propranolol and pindolol, beta-noradrenergic antagonists with affinity for 5-HT1 receptors, antagonized the S-MDMA-induced locomotor hyperactivity. The antagonism by propranolol was stereoselective. In contrast, a beta-noradrenergic antagonist that is a weaker antagonist of 5-HT receptors, betaxolol, was much less effective at blocking the behavioral response to S-MDMA. Among nonselective 5-HT antagonists, methiothepin was effective and methysergide and cyproheptadine were ineffective as antagonists of S-MDMA-induced hypermotility. In other systems, methiothepin has been found to be a good antagonist at 5-HT1B receptors where methysergide and cyproheptadine are ineffective. The 5-HT2 antagonist ritanserin was ineffective in blocking S-MDMA-induced hypermotility. However, ritanserin, methysergide, and cyproheptadine partially reversed the S-MDMA-induced suppression of investigatory responding, suggesting a contribution of 5-HT2 receptor activation to this component of the behavioral response to S-MDMA. This study indicates that S-MDMA produces a characteristic form of locomotor hyperactivity in rats that depends upon activation of 5-HT1-like receptors, possibly of the 5-HT1B subtype.

A D2 dopamine receptor agonist disrupts sensorimotor gating in rats. Implications for dopaminergic abnormalities in schizophrenia

Prepulse inhibition of acoustic startle is deficient in schizophrenic patients and in animals injected with either direct or indirect dopamine (DA) agonists. The present experiments confirmed the hypothesis that the dopaminergic blockade of prepulse inhibition is attributable to the activation of D2 DA receptors. After systemic administrations of the D1 agonist SK&F 38393, the D2 agonist quinpirole, or a combination of the two, rats were tested for prepulse inhibition of the startle response by presenting acoustic stimuli or acoustic stimuli preceded by weak prepulses that inhibit startle. Although the D1 agonist SK&F 38393 had no effect on prepulse inhibition [0.3 to 30.0 mg/kg (1.03 to 102.82 mumols/kg)], the D agonist, quinpirole, blocked prepulse inhibition at doses of 0.3 mg/kg (1.17 mumols/kg) and 0.9 mg/kg (3.51 mumols/kg). Lower doses of quinpirole, 0.03 mg/kg (0.12 mumols/kg) and 0.1 mg/kg (0.39 mumols/kg), were ineffective. When an ineffective dose of quinpirole (0.1 mg/kg) was coadministered with 10.0 mg/kg SKF 38393, prepulse inhibition was reduced relative to saline controls. This reduction of prepulse inhibition is consistent with the synergistic effect of D1 and D2 DA receptor stimulation noted in studies of dopaminergic influences on stereotyped behavior in rats. These findings confirm that a disruption of sensorimotor gating results from D2 dopaminergic stimulation in the rat and extend the applicability of this animal model for the similar behavioral deficits exhibited by schizophrenic patients.