Long-term Changes in Mouse Lung Following Inhalation of a Fibrosis-inducing Dose of 239PuO2: Changes in Collagen Synthesis and Degradation Rates

Summary

Mice were exposed by nose-only inhalation to ²³⁹PuO₂, which resulted in an IAD of 1110 ± 29 Bq. At various times after exposure, rates of collagen metabolism were measured using validated in vivo methods based on the administration of radiolabelled proline, together with a large flooding dose of unlabelled proline and measurement of its incorporation into lung collagen as hydroxyproline. Dramatic increases in both synthesis and degradation rates of collagen were observed. At 54 days after exposure the fractional synthesis rates in experimental mice were almost five times those in controls (control: 3·2 ± 0·6%/day, ²³⁹PuO₂-exposed: 14·5 ± 0·4%/day) and by 300 days synthesis rates, although declining, were still more than double the control values. A similar pattern of change was observed for collagen degradation. The combination of changes in synthesis and degradation rates led to a 60% increase in lung collagen content by 300 days (control: 3·05 ± 0·24 mg/lung, ²³⁹PuO₂-exposed: 4·88 ± 0·42 mg/lung). The data suggest that extensive remodelling of the lung connective tissue matrix occurs during development of fibrosis and that, over long periods of time, small imbalances between synthesis and degradation may result in quite large increases in protein content.     

Radiation Biology and Medicine

Young Beagle dogs were exposed by inhalation to aerosols of ²³⁹PuO₂ and observed for their lifespans as part of a large, ongoing study of the biological effects of inhaled radionuclides. The purpose of our study was to compare certain immune responses of the ²³⁹PuO₂-exposed dogs at middle age (7–10 years old) and old age (12–14 years old), with those of unexposed, age-matched or young (3–4 years old) animals. Some of the aged, exposed dogs had developed lung tumours. Lymphocyte proliferative responses to phytohaemagglutinin (PHA) were lower in aged control dogs than in either young or middle-aged control dogs. Both aged and middle-aged, radiation-exposed dogs had decreased responses to PHA when compared to age-matched controls. Responses to concanavalin A (Con A) were not affected by age in control dogs, but tended to decrease in the oldest group of radiation-exposed dogs. Responses to both PHA and Con A were severely depressed in tumour-bearing dogs. The cytolytic activity of natural killer cells was not affected by age, radiation exposure, or tumour presence. We concluded that inhalation of ²³⁹PuO₂ by young Beagle dogs resulted in an earlier-than-normal decrease in the ability of T cells to respond to mitogenic stimulation. In other words the depressed responses to PHA that were observed might represent radiation-induced, accelerated ageing of the T cell response.     

Translocation of Plutonium from Rat and Monkey Lung after Inhalation of Industrial Plutonium Oxide and Mixed Uranium and Plutonium Oxide

This study was designed to compare the translocation from lung of the Pu contained in the pure and mixed industrial oxides PuO₂ and (U,Pu)O₂. The latter had a Pu content of 20% w/w. For this purpose, young adult male rats and male and female baboons were exposed to a single inhalation of these oxides. Two baboons were exposed to the reference PuO₂, i.e. ²³⁹PuO₂. Rats were killed under anaesthesia 1, 15, 30, 90 and 180 days after exposure, and baboons, also under anaesthesia, 1 year thereafter. The results indicate that lung retention of Pu was independent of the oxide inhaled, but was smaller in rat (12–15% of the initial pulmonary burden, 6 months after exposure) than in baboon (56–80% of this burden, 1 year after exposure). In rat, Pu translocation kinetics were similar for the two industrial oxides, but as from day 15 after inhalation until 6 months thereafter, measurement of Pu deposits in the liver and skeleton showed that translocation of Pu from the mixed oxide was 2–3 times greater than that from the industrial Pu oxide. In baboon, the largest amounts of Pu were retained in the lung and thoracic lymph nodes for the three oxides inhaled. Pu translocation to the liver, skeleton and kidneys, and also urinary Pu excretion, were greater after inhalation of the mixed oxide than after inhalation of the industrial and reference Pu oxides. Nevertheless, the amount of mixed oxide Pu translocated to these sites and excreted in urine remained under 3% of the initial pulmonary burden.     

Absence of genotoxic potential of 902 MHz (GSM) and 1747 MHz (DCS) wireless communication signals: In vivo two-year bioassay in B6C3F1 mice

Purpose: The aim of the present investigation was to determine the incidence of micronuclei in peripheral blood erythrocytes of B6C3F1 mice that had been chronically exposed to radiofrequencies (RF) used for mobile communication.

Materials and methods: ‘Ferris wheels’ were used to expose tube-restrained male and female mice to simulated environmental RF signals of the Global System for Mobile Communications (GSM, 902 MHz) or Digital Cellular System (DCS, 1747 MHz). RF signals were applied to the mice for 2 hours/day on 5 days/week for two years, at maximal whole-body-averaged specific absorption rates of 0.4, 1.3, and 4.0 W/kg body weight. Concurrent sham-exposed mice, cage controls, and positive controls injected with mitomycin C were included in this investigation. At necropsy, peripheral blood smears were prepared, and coded slides were stained using May-Grünwald-Giemsa or acridine orange. The incidence of micronuclei was recorded for each mouse in 2000 polychromatic and 2000 normochromatic erythrocytes.

Results: There were no significant differences in the frequency of micronuclei between RF-exposed, sham-exposed, and cage control mice, irrespective of the staining/counting method used. Micronuclei were, however, significantly increased in polychromatic erythrocytes of the positive control mice.

Conclusions: In conclusion, the data did not indicate RF-induced genotoxicity in mice after two years of exposure.     

Cytogenetic Effects of Microwave Irradiation on Male Germ Cells of the Mouse

Summary

Hybrid male mice were exposed to 2·45 GHz microwaves for 30 min/day, 6 days a week for two consecutive weeks at power densities of 1·0, 100 or 400 W m^?2, with sham-exposed controls. Rectal temperatures before and after exposure were measured on days 1, 6 and 12. Measurements made on day 1 were treated with caution because of heterogeneity in rectal temperatures taken before exposure between the groups of mice given different treatments. On days 6 and 12, rectal temperatures rose by approximately 1°C in mice sham exposed, or exposed to 1 W m^?2 or 100 W m^?2. Only in the group of mice exposed to 400 W m^?2 was the mean rise in rectal temperature during exposure (about 3°C) significantly increased above the sham value. In groups killed 2–3 days after treatment (mainly meiotic exposure) frequencies of chromosome aberrations in spermatocytes showed no significant heterogeneity although the highest frequency of 1·5 per cent was at the highest (400 W m^?2 power density. Another group killed 30 days after 100 W m^?2 exposures (spermatogonial sampling) showed no significant increase over controls in chromosome aberration frequency. There was a small but significant increase in sperm count with increasing power density in mice killed 12–13 days after exposure, but a non-significant one in those exposed as spermatogonia (killed 41 days later). Thus effects were markedly less severe than those reported previously by Manikowska-Czerska et al. (1985) with a very similar radiation regime and were probably caused by the temperature enhancement.     

Chronic exposure of Sprague-Dawley rats to 20 kHz triangular magnetic fields

Purpose:?As a continuing study of 20?kHz triangular magnetic fields (MF) [Lee et al. ], we investigated the chronic toxicity and possible health effects of exposure to 20?kHz MF at the flux density of 30?μT, which is the limit standard for the occupational population in South Korea, with the use of Sprague-Dawley rats.

Materials and methods:?Rats were exposed to 20?kHz triangular MF at 30?μT Root Mean Square for 8?h/day for 18 months. Body and organ weights were measured and urinalysis, hematological and blood biochemistry analyses were performed in individual animals. Histopathological evaluation was also performed for the brain, thymus, lung, heart, liver, kidney, intestine and reproductive organs, including tumour tissue.

Results:?The mortality patterns in male or female rats exposed to magnetic fields were compared to the mortality patterns found in sex-matched sham control animals. Significant alteration of body weight was not observed with MF exposure. No significant differences were seen in sham-exposed and MF-exposed animals based on urological factors, hematological factors and blood biochemistry. Total tumour incidence was not different between sham-exposed and MF-exposed animals.

Conclusion:?Our results suggest that chronic exposure to 20?kHz triangular MF with 30?μT flux density did not increase toxicity in rats.     

One-year,simultaneous combined exposure of CDMA and WCDMA radiofrequency electromagnetic fields to rats

Purpose:?We investigated whether one-year, long-term, simultaneous exposure to code division multiple access (CDMA; 849 MHz) and wideband code division multiple access (WCDMA; 1.95 GHz) radiofrequencies (RF) would induce chronic illness in Sprague-Dawley (SD) rats.

Materials and methods:?Two groups of 40 SD rats (50% males and females in sham and exposed groups) were exposed to CDMA and WCDMA RF simultaneously at 2.0 W/kg for 45 min/day (total 4.0 W/kg), 5 days per week for a total of one year. Body and organ weight measurements, urinalysis, haematological and blood biochemical analysis, and histopathological evaluations were performed.

Results:?The mortality patterns in male and female rats exposed to RF were compared with those found in gender-matched sham control animals. No significant alteration in body weight was observed with the simultaneous combined RF exposure. Most RF-exposed rats showed no significant alteration, based on urinalysis, haematology, blood biochemistry, or histopathology. However, some altered parameters of the complete blood count and serum chemistry were seen in RF-exposed rats. The total tumour incidence was not different between sham-exposed and RF-exposed animals.

Conclusions:?Our results suggest that one-year chronic exposure to CDMA (849 MHz) and WCDMA (1.95 GHz) RF simultaneously at 2.0 W/kg for 45-min RF exposure periods (total, 4 W/kg) did not increase chronic illness in rats, although there were some altered parameters in the complete blood count and serum chemistry.     

Effect of Electromagnetic Pulses (EMP) on associative learning in mice and a preliminary study of mechanism

Abstract

Purpose: To investigate the effects of electromagnetic pulses (EMP) on associative learning in mice and test a preliminary mechanism for these effects.

Materials and methods: A tapered parallel plate gigahertz transverse electromagnetic (GTEM) cell with a flared rectangular coaxial transmission line was used to expose male BALB/c mice to EMP (peak-intensity 400 kV/m, rise-time 10 ns, pulse-width 350 ns, 0.5 Hz and total 200 pulses). Concurrent sham-exposed mice were used as a control. Associative learning, oxidative stress in the brain, serum chemistry and the protective action of tocopherol monoglucoside (TMG) in mice were measured, respectively.

Results: (1) Twelve hour and 1 day post EMP exposure associative learning was reduced significantly compared with sham control (p < 0.05) but recovered at 2 d post EMP exposure. (2) Compared with the sham control, lipid peroxidation of brain tissue and chemiluminescence (CL) intensity increased significantly (p < 0.05), while the activity of the antioxidant enzymes Superoxide Dismutase [SOD], Glutathione [GSH], Glutathione Peroxidase [GSH-Px], Catalase [CAT]) decreased significantly (p < 0.05) at 3 h, 6 h, 12 h and 1 d post EMP exposure. All these parameters recovered at 2 d post EMP exposure. (3) No significant differences between the sham control group and EMP exposed group were observed in serum cholesterol and triglycerides. (4) Pretreatment of mice with TMG showed protective effects to EMP exposure.

Conclusions: EMP exposure significantly decreased associative learning in mice and TMG acted as an effective protective agent from EMP exposure. This mechanism could involve an increase of oxidative stress in brain by EMP exposure.     

Effect of whole-body exposure to the 848.5 MHz code division multiple access (CDMA) electromagnetic field on adult neurogenesis in the young,healthy rat brain

Abstract

Introduction: Whether exposure to the 848.5 MHz code division multiple access (CDMA) signal affects adult neurogenesis is unclear.

Materials and methods: An animal experiment was performed with a reverberation chamber designed as a whole-body CDMA exposure system. Male Sprague-Dawley rats were assigned to three groups (n = 6 per group): Cage-control, sham-exposed, and CDMA-exposed groups. Rats in the CDMA-exposed group were exposed to the CDMA signal at a 2 W/kg whole-body specific absorption rate (SAR) for 1 or 8 h daily, 5 days per week, for 2 weeks. Rats received a single intraperitoneal injection of Bromodeoxyuridine (BrdU) to label proliferative cells daily for the last five consecutive days of CDMA signal exposure. An unbiased stereological method was used to estimate the number of BrdU⁺ cells in the subventricular zone (SVZ) and dentate gyrus (DG).

Results: We found no significant changes in the number of BrdU⁺ cells in the SVZ or DG in the CDMA-exposed rats, compared with rats in the cage-control and sham-exposed groups (p > 0.05).

Conclusion: Our results suggest that exposure to the CDMA signal does not affect neurogenesis in the adult rat brain, at least under our experimental conditions.     

The effects of electromagnetic pulses (EMP) on the bioactivity of insulin and a preliminary study of mechanism

Purpose:?To investigate the effects of electromagnetic pulse (EMP) exposure on the bioactivity of insulin and a preliminary mechanism for these effects.

Materials and methods:?A tapered parallel plate Gigahertz Transverse Electromagnetic (GTEM) cell with a flared rectangular coaxial transmission line was used to expose the insulin solution to EMP. Concurrent sham-exposed insulin solutions were used as a control. The effect of EMP-exposed insulin on fasting blood glucose levels of type I diabetes model mice, the effect of EMP on binding affinity between insulin and its receptor and the effect of EMP on insulin's fluorescence intensity were detected, respectively.

Results:?(i) After EMP exposure, compared with sham-exposed insulin, the bioactivity of insulin in decreasing fasting blood glucose levels in type I diabetes model mice was reduced significantly (p?=?0.023). (ii) Compared with sham-exposed insulin group, the percentage fluorescein isothiocyannate (FITC) labelling of HL-7702 cells was significantly reduced in the EMP-exposed insulin group (22.7–13.8%, respectively). (iii) Compared with sham-exposed insulin, the fluorescence intensity was significantly reduced in EMP-exposed insulin (p?<?0.001).

Conclusions:?EMP exposure significantly decreased the bioactivity of insulin to reduce the blood glucose levels in type I diabetic mice. This could be due to a decreased binding affinity between insulin and its receptor. This mechanism could involve an alteration of insulin's' conformation caused by EMP exposure.     

Effects of IL-4 on pulmonary fibrosis and the accumulation and phenotype of macrophage subpopulations following thoracic irradiation

Purpose: Thoracic irradiation injures lung parenchyma, triggering inflammation and immune cell activation, leading to pneumonitis and fibrosis. Macrophage polarization contributes to these processes. Since IL-4 promotes pro-fibrotic macrophage activation, its role in radiation-induced lung injury was investigated.

Materials and methods: Lung macrophage subpopulations were characterized from 3–26 weeks following exposure of WT and IL-4?/? mice to 0 or 12.5 Gray single dose thoracic irradiation.

Results: Loss of IL-4 did not prevent fibrosis, but blunted macrophage accumulation within the parenchyma. At 3 weeks following exposure, cell numbers and expression of F4/80 and CD206, an alternative activation marker, decreased in alveolar macrophages but increased in infiltrating macrophages in WT mice. Loss of IL-4 impaired recovery of these markers in alveolar macrophages and blunted expansion of these populations in infiltrating macrophages. CD206+ cells were evident in fibrotic regions of WT mice only, however Arg-1+ cells increased in fibrotic regions in IL-4?/? mice only. Radiation-induced proinflammatory Ly6C expression was more apparent in alveolar and interstitial macrophages from IL-4?/? mice.

Conclusions: IL-4 loss did not prevent alternative macrophage activation and fibrosis in irradiated mice. Instead, a role is indicated for IL-4 in maintenance of macrophage populations in the lung following high single dose thoracic irradiation.     

FDG-PET/CT finding of high uptake in pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare lung disease characterized by progressive intra-alveolar calcification. We present a case of PAM with abnormal accumulation of ¹⁸F-fluorodeoxyglucose (FDG) in both lungs. A 55-year-old man was referred to our hospital for progressive dyspnea. He had been diagnosed with PAM 25 years earlier by transbronchial lung biopsy. High-resolution computed tomography revealed multiple dense calcifications with little aerated lung. Combined positron emission tomography and computed tomography using ¹⁸F-FDG (FDG-PET/CT) showed the abnormal accumulation of FDG in both lungs with a maximal standardized uptake value of 7.3. High FDG uptake was observed mainly in the lung regions showing sparing calcification. The patient died of respiratory failure a month later and an autopsy revealed no significant inflammatory changes in either lung. We suspect that the markedly enhanced pulmonary FDG uptake may have some relation to the pathophysiology of PAM.     

Static magnetic field attenuates mortality rate of mice by increasing the production of IL-1 receptor antagonist

Purposes: Disseminated intravascular coagulation (DIC) is a complex systemic thrombohemorrhagic disorder involving intravascular coagulation and hemorrhage. The aim of this study is to test whether static magnetic field (SMF) is effective in attenuating lipopolysaccharide (LPS)-induced DIC.

Materials and methods: In vivo experiments were performed in this study using male BALB/cByJ mice. An intraperitoneal injection of 50 mg/kg LPS was shown to lead to approximately 50% mortality and this dose was used in subsequent experiments. To test the effects of SMF on the survival rate of LPS-induced animals, the mice were exposed to 0.25-T SMF for 2 h before LPS injection. In addition, the effect of a 2-h SMF treatment on the production of anti-inflammatory cytokines was evaluated.

Results: In the first set of experiments, we found that the survival rate was higher in the SMF-exposed group than in the sham-exposed group. The circulating platelet (PLT) counts in the SMF-exposed mice were significantly higher than in the unexposed animals. However, no significant changes in inflammatory cytokine, including tumour necrosis factor-α (TNF-α), interleukin-1α (IL-1α), interleukin-6 (IL-6) and monocyte chemotactic protein 1 (MCP-1), in plasma were found after SMF treatment. The results from the second experiment showed that the plasma levels of interleukin-1 receptor antagonist (IL-1ra) were higher in the SMF-exposed group than in the sham group.

Conclusions: Exposure to an SMF increases the plasma levels of IL-1ra. This effect may inhibit the reduction in PLT in plasma, resulting in prevention in LPS induced DIC.     

Pulmonary alveolar microlithiasis: imaging characteristics of planar and SPECT/CT bone scan versus 18F-FDG and 18F-sodium fluoride PET/CT scanning

Pulmonary alveolar microlithiasis (PAM) is a very rare disease in which multiple microscopic calcium phosphate microliths are deposited within the alveoli of both lungs. A lung biopsy is considered to be definitive for final diagnosis; however, non-invasive imaging modalities such as chest X-ray, HRCT scan and ^99mTc-MDP bone scan suggest the diagnosis in the vast majority of patients. Although ¹⁸F-FDG PET/CT has been tried to characterize the disease, ¹⁸F-sodium fluoride PET/CT as a ‘proof-of-principle’ was tried for the first time in a known case of PAM in order to characterize the lung lesions. Interestingly, we noted that ¹⁸F-sodium fluoride PET/CT is a superior modality in characterization and assessment of the extent of disease in PAM compared to all other non-invasive imaging modalities. Thus, we recommend that ¹⁸F-sodium fluoride PET/CT should be the investigation of choice in PAM.     

Repeated exposure to low‐level extremely low frequency‐modulated microwaves affects baseline and scopolamine‐modified electroencephalograms in freely moving rats

Purpose: To compare in the electroencephalogram of rats the effects of scopolamine (an acetylcholine receptor antagonist) alone and after repeated exposure to low‐level microwaves modulated at extremely low frequency.

Materials and methods: Averaged frequency spectra (0.5–30?Hz) of the electroencephalogram were studied in freely moving rats with carbon electrodes implanted into the somatosensory cortex. The rats were repeatedly (3 days, 30?min?day^?1) exposed to low‐intensity (?0.3?mW?cm^?2) microwaves (915?MHz, 20‐ms pulse duration), amplitude modulated (square‐wave) at extremely low frequency (4?Hz).

Results: The exposure to extremely low frequency microwaves alone significantly enhanced the fast electroencephalographic rhythms (18–30?Hz). This effect was observed neither in subsequent sham‐exposure experiment nor in radiation‐naïve animals. In the microwave‐exposed rats, scopolamine (0.1?mg?kg^?1, subcutaneously) did not cause a slowing in the electroencephalogram that was shown in non‐exposed rats. A similarity between the scopolamine‐induced electroencephalogram effect in the microwave‐exposed rats and that of physostigmine (enhancing the acetylcholine level in the brain) in radiation‐naïve animals was noted. This paradoxical phenomenon stimulates new experimentation for understanding its mechanism(s).

Conclusions: The data obtained provide additional evidence that repeated low‐level exposure to extremely low frequency microwaves can modify an activity of cholinergic system in the brain.     

Micronucleus frequency in erythrocytes of mice after long-term exposure to radiofrequency radiation

Purpose: The aim of the study was to investigate genotoxicity of long-term exposure to radiofrequency (RF) electromagnetic fields by measuring micronuclei in erythrocytes. The blood samples were collected in two animal studies evaluating possible cocarcinogenic effects of RF fields.

Methods: In study A, female CBA/S mice were exposed for 78 weeks (1.5 h/d, 5 d/week) to either a continuous 902.5 MHz signal similar to that emitted by analog NMT (Nordic Mobile Telephone) phones at a whole-body specific absorption rate (SAR) of 1.5 W/kg, or to a pulsed 902.4 MHz signal similar to that of digital GSM (Global System for Mobile Communications) phones at 0.35 W/kg. A third group was sham-exposed, and a fourth group served as cage controls. All but the cage control animals were exposed to 4 Gy of x-rays during three first weeks of the experiment. In study B, female transgenic mice (line K2) and their nontransgenic littermates were exposed for 52 weeks (1.5 h/d, 5 d/week). Two digital mobile phone signals, GSM and DAMPS (Digital Advanced Mobile Phone System), were used at 0.5 W/kg. All but the cage-control animals were exposed 3 times per week to an ultraviolet radiation dose of 1.2 MED (minimum erythema dose).

Results and conclusions: The results did not show any effects of RF fields on micronucleus frequency in polychromatic or normochromatic erythrocytes. The results were consistent in two mouse strains (and in a transgenic variant of the second strain), after 52 or 78 weeks of exposure, at three SAR levels relevant to human exposure from mobile phones, and for three different mobile signals.     

Radiation decreases murine small intestinal HCO3− secretion

Purpose:?While secretagogue-induced diarrhea is rich in chloride (Cl^?) and bicarbonate (HCO₃ ^?) anions, little is known about diarrhea or its anionic composition following irradiation. We performed studies to characterize the differences between cyclic adenosine monophosphate (cAMP)-stimulated anion secretions in irradiated and non-irradiated mice.

Materials and methods:?HCO₃ ^? secretion was examined in basal, cAMP-stimulated, and irradiated jejunal tissues from BALB/c (Bagg albino) mice. The abdomens of the mice were γ-irradiated using a caesium-137 source.

Results:?Ussing-chamber experiments performed in an HCO₃^?-containing, Cl^?-free solution on the bath side showed inhibition of HCO₃^? in irradiated mice. Non-irradiated mice exhibited bumetanide-sensitive and insensitive current, while irradiated mice displayed bumetanide-sensitive current. pH-stat experiments showed inhibition of basal and cAMP-stimulated HCO₃^? secretions in irradiated mice. Immunohistochemistry and Western blot analysis displayed a sodium-bicarbonate cotransporter expression in the villus and not the crypt of non-irradiated mice, while its expression and protein levels decreased in irradiated mice.

Conclusions:?Anion secretions in irradiated mice, being primarily Cl^? and minimally HCO₃^?, differ from that of secretagogue-induced anion secretions. Understanding anion loss will help us correct electrolyte imbalances, while reduced HCO₃^? secretion in the upper-gastrointestinal tract might also have implications for irradiation-induced nausea and vomiting.     

Hyperreflexia induced by XLR-11 smoke is caused by the pyrolytic degradant

Purpose

Some of the synthetic cannabinoids, often found in recreational drugs of the herbal form, reportedly induce a generalized seizure in drug abusers immediately after smoking. However, it is still unclear what elicits the sensorimotor responses, particularly in the case of hyperreflexia or excitatory behavior during the synthetic cannabinoid exposure. The purpose of this study was to explore the mechanism underlying the hyperreflexia induced by smoke intoxication of XLR-11 [(1-(5-fluoropentyl)-1H-indol-3-yl)(2,2,3,3-tetramethylcyclopropyl)methanone].

Methods

Locomotor activity and body temperature of mice were measured using an implanted Nano-Tag device. The intensity of catalepsy was determined by the bar test. The extracellular dopamine levels in the nucleus accumbens and glutamate levels in the hippocampus were measured by in vivo microdialysis using electrochemical detector-coupled high-performance liquid chromatography and by in vivo enzyme-based biosensor method, respectively.

Results

Mice exposed to the smoke of XLR-11 exhibited hyperreflexia at the very early phase, followed by hypothermia and catalepsy. The XLR-11 smoke contained XLR-11 and XLR-11 degradant at a ratio of approximately 1:25. Mice treated intraperitoneally with XLR-11 degradant at a dose comparable to the smoke inhalation experiment showed a hyperreflexic effect immediately after the treatment, but XLR-11 showed no such effect. The effects of XLR-11 degradant were significantly suppressed by pretreatment with AM-251, a CB₁ receptor antagonist. Extracellular dopamine and glutamate levels showed no evidence of involvement in the XLR-11 degradant-induced hyperreflexia; on the other hand gabapentin, a GABAergic antiepileptic, significantly suppressed the enhanced locomotor activity.

Conclusions

The hyperreflexic effect of XLR-11 degradant is mediated by the CB₁ receptor and possibly by GABAergic function.

     

Influence of electromagnetic fields on reproductive system of male rats

Abstract

Purpose: Reports of declining male fertility have renewed interest in the role of environmental and occupational exposures in the etiology of human infertility. The aim of the present work was to investigate the effect of 10 GHz exposure on the male Wistar rat's reproductive system and to find out the possible causative factors.

Materials and methods: The study was divided into sham-exposed and exposed groups. Seventy day-old rats were exposed to 10 GHz microwave radiation for 2 h per day for 45 days at power density 0.21 mW/cm² and specific absorption rate (SAR) of 0.014 W/kg. After the end of the experiment, blood samples were collected for the estimation of in vivo chromosomal aberration damage and micronucleus test. Spermatozoa were taken out for estimation of Caspase-3, comet assay, testosterone and electron microscopy and compared with sham-exposed.

Results: The study of scanning electron microscopic revealed shrinkage of the lumen of the seminiferous tubules. Apoptotic bodies were found in exposed group. A flow cytometry examination showed formation of micronuclei body in lymphocytes of exposed group. Comet assay confirmed DNA (deoxyribonucleic acid) strand break. Testosterone level was found significantly decreased with the shrinkage of testicular size.

Conclusions: 10 GHz field has an injurious effect on fertility potential of male-exposed animals.     

The histopathological evaluation of the effectiveness of melatonin as a protectant against acute lung injury induced by radiation therapy in a rat model

Purpose: This study presents the histopathological evaluation of the effectiveness of melatonin as a protectant against acute lung injury induced by radiation therapy.

Materials and methods: Thirty-two Wistar rats were divided into four groups. The rats in Group 1 received melatonin and underwent radiation therapy. The rats in Group 2 received no melatonin and underwent radiation therapy. The rats in Group 3 received melatonin and underwent sham radiation therapy. The rats in Group 4 received no melatonin and underwent sham radiation therapy. Melatonin was administered at a dose of 100 mg/kg using an intraperitoneal injection. Radiation therapy was delivered on a Cobalt-60 unit using a single fraction of 18 Gy through an anterior portal covering the right lung in entirety. The rats underwent euthanasia at 6 weeks following radiation therapy. The lungs were dissected and blinded histopathological evaluation was performed.

Results: Concerning the right lung, a decrease in intra-alveolar edema and intra-alveolar erythrocytes was observed despite an increase in activated macrophages, intra-alveolar fibrosis, hyaline arteriosclerosis and alveolar wall thickness for the rats in Group 1 as compared to the rats in Group 2. Concerning the left lung, a decrease in alveolar neutrophils and intra-alveolar erythrocytes was evident despite an increase in activated macrophages, hyaline arteriosclerosis and alveolar wall thickness for the rats in Group 1 as compared to the rats in Group 2.

Conclusions: This study puts forward the histopathological evidence regarding the effectiveness of melatonin as a protectant against acute lung injury induced by radiation therapy through restrained inflammation, regrettably at the expense of promoted fibrosis. The effectiveness of melatonin as a protectant against acute lung injury induced by radiation therapy needs to be evaluated further for the unresolved concerns regarding the safety.