Evidence for oxidative damage to red blood cells in mice induced by arsine gas

In animals and human beings exposed to arsine gas (AsH3) a severe and fulminant lysis of erythrocytes occurs. Little is known about the effects of subchronic exposure on the hematopoietic system or about the mechanism of hemolysis produced by arsine gas. To examine these, we exposed male and female mice to 0.000, 0.025, 0.500 and 2.500 ppm arsine gas for 6 h a day, 5 days a week during a 90-day period. After 5, 15, and 90 days of exposure, blood was collected and routine hematologic profiles were performed to document the effects of arsine gas on peripheral blood. A moderate hemolytic anemia, indicated by decreases in erythrocyte counts, hematocrits, hemoglobin concentrations and increases in mean corpuscular hemoglobins and mean corpuscular hemoglobin concentrations, was seen in blood samples collected after 5 days of exposure. In blood collected after 15 and 90 days of exposure, the anemia was less severe but a greater increase in mean corpuscular volumes and absolute reticulocyte counts revealed an active regenerative response. Higher concentrations of methemoglobin in animals in the 2.500 ppm exposure group (measured after 90 days of exposure) indicated that the rate of oxidation of heme (ferrous to ferric) increased due to exposure to arsine gas. Additionally, the presence of Heinz bodies in blood smears stained with brilliant cresyl blue and decreases in reduced glutathione concentrations in red blood cells exposed to arsine gas in vitro provide evidence that the mechanism of hemolysis involves depletion of intracellular reduced glutathione resulting in an oxidation of sulfhydryl groups in hemoglobin and possibly red cell membranes.     

Behavioral effects in adult mice exposed to perfluorooctane sulfonate (PFOS)

Nowadays, very little information concerning the effects on behavior in mammals of perfluorooctane sulfonate (PFOS), a widely distributed persistent environmental pollutant, is available. In the present study, we assessed the behavioral effects of PFOS on 3 months old mice after 1 month of exposure to this pollutant. Thirty adult mice were divided into three groups. Animals were given by gavage 0, 3, and 6 mg PFOS/kg/day for four consecutive weeks. After the treatment period, mice were evaluated for several skills by testing motor and sensory function by means of a functional observation battery (FOB), general activity and exploratory behavior in an open-field, and learning and memory in a water maze task. One week after behavioral testing, serum was collected for corticosterone analyses. No adverse effects were observed in the FOB. In general terms, activity in the open-field was similar in all groups being the only observed differences limited to the group given PFOS at 3mg/kg/day (spent less time in the center) and the group exposed to 6 mg PFOS/kg/day) (reduced rate of vertical activity). Concerning the effects of PFOS in the water maze, although all animals learned the task, no effect of the dose was observed during the acquisition. In the retention test, a deleterious effect of PFOS was noted. These results indicate that PFOS exposure induced only slight behavioral effects in adult male mice.     

An analysis of drug effects in mice exposed to a simple novel environment

The effects of orally administered drugs on the ambulatory activity of mice placed into a novel environment were investigated. Chlordiazepoxide or diazepam increased ambulatory activity; this effect occurred during the initial minutes of testing but in later minutes activity was reduced. Amylobarbitone, meprobamate or high doses of atropine produced more sustained increases in activity. Ambulatory activity was not increased by chlordiazepoxide or amylobarbitone in mice familiar with the test situation; in these conditions activity was increased by meprobamate and atropine. The observed differences between drugs were discussed in terms of habituation and interactions with environmental novelty.     

Failure to detect dominant-lethal mutations and effects on reproductive capacity in mice exposed to dihydroergotoxine mesylate

Triethylenemelamine (TEM), a known chemical mutagen, and dihydroergotoxine mesylate (DHETM, Hydergin), an ergot derivative, were tested for mutagenic effects by means of the dominant-lethal test in male mice and the total reproductive capacity test in female mice. In contrast to TEM, which proved to be strongly effective in these test systems, DHETM did not show any effect. It is concluded that this drug, at both subtoxic and pharmacologically active dose-levels, has no potential to affect spermatogenic and oogenic cells.     

Photoprotective effects of Romanian propolis on skin of mice exposed to UVB irradiation

We aimed at investigating the antioxidant, antiinflamatory, antiapoptotic and antigenotoxic effects of a Romanian Propolis (RP) extract in two concentrations (RP1 3 mg, respectively RP2 1.5 mg polyphenols/cm²), topically administered, either prior to or after UVB exposure, in a Swiss mouse model. Our results showed that both concentrations of RP extract, independent of the time of administration, significantly attenuated the malondialdehyde (MDA) formation and restored glutathione peroxidase (GPx) activity. However, the 8-hydroxy-2-deoxy-guanosine (8-oxo-dG), nitric oxide (NO) and glutathione (GSH) levels were not influenced by UVB exposure and RP treatment. Interleukin (IL)-6 levels were significantly decreased by RP treatment, both before and after UVB-exposure. RP2 extract, in both regimens, significantly reduced the epidermal hyperplasia and dermal inflammation, whereas RP1 pre-treatment diminished only the dermal inflammation. The effect of our RP extract in terms of reduction of sunburn cell formation and of activated caspase-3 and TUNEL-positive cells was observed in both subsets of the experiment, RP2 having a slightly better protective effect as compared to RP1. The antigenotoxic effect of RP was demonstrated by significantly reduced cyclobutane pyrimidine dimers (CPDs) formation. Our results suggest that RP extract might be a potential chemopreventive candidate by modulation of multiple UVB-induced signaling pathways in skin.     

Arsenobetaine is not a major metabolite of arsine gas in the rat

Many organisms can easily dispose of toxic inorganic arsenic species through gradual methylation of the element and further urinary excretion. In order to clarify the urinary excretion of arsenobetaine observed in a human case of intoxication by arsine, the capacity of highly methylated arsenical synthesis has been investigated in rats acutely exposed during 1 h to increasing concentrations of the same gas [4 to 80 mg AsH₃/m³]. Urinary metabolites of arsenic were determined with good agreement in two (Belgian and Italian) laboratories using two different analytical procedures. The sum of inorganic, mono- and dimethylated metabolites of arsenic in urine was shown to be related to the intensity of exposure to arsine. A biphasic relationship was observed: 1 h exposure to >60 mg AsH₃/m³ led to metabolite excretion which is roughly 10 times higher than for exposure levels below that limit, suggesting the saturation of a binding site reserve and the availability for metabolism of a greater proportion of the As absorbed above this threshold. Arsenobetaine production, if any, could only be detected when its presence in food was excluded; in addition, amounts appeared negligible and could be disregarded as a common arsenic metabolite in rats. Received: 26 June 1998 / Accepted: 26 August 1998     

中药952对射线所致小鼠肠道微生态失调的调整作用

中药952治疗射线所致微生态失调作用非常显著(P<0.01)。与阳性对照组比具有显著优势(P<0.05)。     

The temporal profile of cytokines in the bronchoalveolar lavage fluid in mice exposed to the industrial gas phosgene

Diagnosis of an exposure to airborne toxicants can be problematic. Phosgene is used widely in industry for the production of many synthetic products, such as polyfoam rubber, plastics, and dyes. Although nearly 100% of the gas is consumed during processing, there is the potential problem of accidental or even intentional exposure to this irritant/choking agent. Exposure to phosgene has been known to cause latent life-threatening pulmonary edema. A major problem is that there is a clinical latency phase from 3 to 24 h in people before irreversible acute lung injury occurs. Assessment of markers of acute lung injury after a suspected exposure would be useful in developing rational treatment strategies. These experiments were designed to assess bronchoalveolar lavage fluid (BALF) for the presence of the early markers of exposure to phosgene in mice from 1 to 72 h after exposure. Separate groups of 40 CD-1 male mice (Crl:CD-1(ICR)BR) weighing 29 +/- 1 g were exposed whole-body to either air or a concentration x time (c x t) amount of 32 mg/m(3) (8 ppm) phosgene for 20 min (640 mg x min/m(3)). BALF from air- or phosgene-exposed mice was taken at 1, 4, 8, 12, 24, 48, and 72 h postexposure. After euthanasia, the trachea was excised, and 800 micro l saline was instilled into the lungs and washed 5x. BALF was assessed for interleukin (IL)-4, IL-6, tumor necrosis factor (TNF) alpha, IL-1alpha, macrophage inflammatory protein (MIP)-2, and IL-10. At 4 h postexposure, IL-6 was 15-fold higher for phosgene-exposed mice than for the time-matched air-exposed control group. At 8 and 12 h, IL-6, IL-1beta, MIP-2, and IL-10 were significantly higher in phosgene-exposed mice than in time-matched air-exposed controls, p < or = 0.05 to p < or = 0.001, whereas TNF alpha reached peak significance from 24 to 72 h. IL-4 was significantly lower in the phosgene-exposed mice than in the air-exposed mice from 4 to 8 h after exposure. These data show that BALF is an important tool in assessing pro- and anti-inflammatory markers of phosgene-induced acute lung injury and that knowledge of these temporal changes may allow for timely treatment strategies to be applied.     

Male-mediated F1 effects in mice exposed to nonylphenol or to a combination of X-rays and nonylphenol

Nonylphenol (NP) is an environmental chemical with estrogenic activity. Exposure of the general population to radiation and NP is, very often, unavoidable because of the presence of both agents in the environment of human life and work. The aim of the study was to investigate the effect of subchronic 8-week exposure to NP alone or in combination with X-rays on sperm quantity and quality and on the possibility of the transmission of mutations induced in germ cells to the next generation. Eight-week exposure to NP and X-ray/NP combination diminished sperm count and increased the percent of abnormal spermatozoa, as well as having increased DNA damage in gametes. Some of those effects remained up to 8 weeks after the end of exposure. The exposure of males to 50?mg/kg body weight (b.w.) of NP and to 0.05 Gy + 25?mg/kg b.w. NP daily significantly decreased the percent of pregnant females. The fertilization ability of male mice was not diminished. Combined exposure to low doses of both agents significantly increased the mean number of dead implantations per pregnant female and the percentage of skeletal malformations. Results showed that mutations induced in germ cells by subchronic exposure to NP and to combined X-ray/NP exposure may be transmitted to the F1 generation via sperm.     

Male-mediated F1 effects in mice exposed to nonylphenol or to a combination of X-rays and nonylphenol

Nonylphenol (NP) is an environmental chemical with estrogenic activity. Exposure of the general population to radiation and NP is, very often, unavoidable because of the presence of both agents in the environment of human life and work. The aim of the study was to investigate the effect of subchronic 8-week exposure to NP alone or in combination with X-rays on sperm quantity and quality and on the possibility of the transmission of mutations induced in germ cells to the next generation. Eight-week exposure to NP and X-ray/NP combination diminished sperm count and increased the percent of abnormal spermatozoa, as well as having increased DNA damage in gametes. Some of those effects remained up to 8 weeks after the end of exposure. The exposure of males to 50?mg/kg body weight (b.w.) of NP and to 0.05 Gy + 25?mg/kg b.w. NP daily significantly decreased the percent of pregnant females. The fertilization ability of male mice was not diminished. Combined exposure to low doses of both agents significantly increased the mean number of dead implantations per pregnant female and the percentage of skeletal malformations. Results showed that mutations induced in germ cells by subchronic exposure to NP and to combined X-ray/NP exposure may be transmitted to the F1 generation via sperm.     

Immunotoxicity studies in mice exposed to methyl isocyanate

The effects of methyl isocyanate (MIC) on systemic immunity were evaluated in female B6C3F1 mice exposed via inhalation to 0, 1, or 3 ppm for 6 hr per day on four consecutive days. Humoral immunity, measured as the antibody response to sheep erythrocytes, and natural killer cell activity were not affected by MIC. Furthermore, resistance to the infectious agents Listeria monocytogenes, mouse malaria parasite, and influenza virus, or to B16F10 transplantable tumor cells, was not compromised by MIC exposure. Although lymphoproliferative responses to mitogens were not significantly suppressed, the response of splenic lymphocytes to allogeneic leukocytes in a mixed leukocyte response (MLR) was suppressed in a dose-related fashion and differed significantly from the control response at the 3-ppm level. These studies indicate that MIC exposure in mice does not severely alter systemic immunity. The moderate changes detected in immune function may be a secondary consequence of respiratory toxicity which occurred in these animals.     

硫丹对小鼠子宫内膜细胞的增殖作用

目的　研究硫丹对小鼠子宫内膜细胞的增殖作用。方法　将成年雌性小鼠去势后 ,给予不同剂量的硫丹0 5、1 5、3 0mg (kg·d)连续 5d ,观察子宫内膜细胞有丝分裂指数和嗜银染色颗粒数。结果　给硫丹低、中、高 3个剂量组有丝分裂指数的中位数分别为 3 0、3 5和 4 75 ,均高于阴性对照组 (2 0 ) ,差异有显著性 (P <0 0 1) ,且有明显的剂量 效应关系。同时各组之间的嗜银染色颗粒数差异有显著性 (P <0 0 1) ,阴性对照组、硫丹低、中、高剂量组和阳性对照组的均值分别为 2 12、2 77、3 3 9、3 88、4 44 ,给硫丹的各剂量组都比阴性对照组高 ,并有明确的剂量 效应关系。结论　硫丹能促进子宫内膜细胞DNA的转录和复制 ,加速细胞的分裂和增殖 ,因此 ,推断它在小鼠体内可能具有雌激素样作用     

Nicotine effects on the activity of mice exposed prenatally to the nicotinic agonist anatoxin-a

Anatoxin-a is a nicotinic agonist produced by several genera of cyanobacteria, and has caused numerous deaths of wildlife, livestock and domestic animals world-wide. Several studies in the literature have shown that exposure of mice and rats to nicotine early in development alters its effects when the rodents are subsequently challenged with nicotine. We therefore determined the effect of nicotine on the motor activity of adult mice that had been exposed prenatally to anatoxin-a. Pregnant CD-1 mice received either saline vehicle or one of two doses of (+/-) anatoxin-a (125, 200 microg/kg), i.p., on GD13-17. As adults (8 months), control mice of both genders were used to determine the effect of nicotine (0, 0.1, 0.3, 1.0 or 3.0 mg/kg, s.c.) on motor activity measured for 30-min in a photocell device. Under these conditions, nicotine produced dose-related decreases in both horizontal and vertical activity, with an ED50 estimated to be 0.65 mg/kg. Next, additional control mice and mice exposed prenatally to anatoxin-a received the nicotine ED50 and saline vehicle, in a counterbalanced fashion, with one week separating treatments. Nicotine decreased both horizontal and vertical activity in all mice, regardless of prenatal anatoxin-a treatment. Thus, no enduring effects of prenatal anatoxin-a were obtained in adult mice following nicotine challenge.     

Reproductive and genomic effects in testes from mice exposed to the water disinfectant byproduct bromochloroacetic acid

A byproduct of drinking water disinfection, bromochloroacetic acid (BCA), acts as a reproductive toxicant in rats. To determine if BCA produces similar reproductive toxicity in mice, juvenile and adult C57BL/6 males were exposed to 0, 8, 24, 72 or 216 mg/kg of BCA once daily for 14 days. Five of 12 animals from each dose-group were sacrificed at the end of dosing, and testes, epididymes, and seminal vesicles harvested and weighed. Seven mice from each dose-group (including juvenile-exposed mice, following a 14-week maturation period) were used in a 40-day sequential breeding assay to determine if BCA targets a particular phase of spermatogenesis. No significant effects were observed in mice exposed to BCA as juveniles, and there were no effects on fertility by 14 weeks after dosing. However, effects were observed in adult-exposed mice over the first 10 days after BCA exposure: mean number of litters/male, percentage of litters/female bred, and total number of fetuses/male were all reduced by 72 and 216 mg/kg BCA. These results in adult mice indicate BCA disrupted differentiation of spermatids during dosing and the first 10 days of mating, and are consistent with the spermatid retention and atypical residual bodies observed in animals exposed to 72 and 216 mg/kg BCA. To investigate mechanisms involved, we utilized cDNA microarrays containing 950 testis-expressed genes to profile gene expression from Control and BCA-treated mice. Statistical analyses of microarray results identified 40 well-characterized genes differentially expressed in a dose responsive manner as a result of BCA exposure. Microarray results were supplemented with quantitative real-time PCR and Westerns for several genes and proteins. The 40 genes whose expression was altered by BCA are involved in numerous biological processes including: cell communication and adhesion, cell cycle and cell proliferation, metabolism, signal transduction, stress response, and spermatogenesis and male fertility. Modulated expression of these genes, particularly the 15 expressed in Sertoli cells and spermatids, offers new insights into potential mechanisms of BCA toxicity in the mouse testis.     

Immune alterations in mice exposed to the herbicide simazine

Simazine, a triazine herbicide, was investigated for its in vivo immunomodulatory properties. Male C57Bl/6 mice were treated with vehicle or 300 or 600 mg/kg body weight (bw) simazine daily orally for 4 wk. The immune system was evaluated by the antibody response to sheep red blood cells (SRBC; plaque assay and serum immunoglobulin G), natural killer (NK) and macro-phage activities, lymphocyte subpopulations in the spleen and thymus, and concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated lymphocyte proliferation using splenocytes. Body weight and spleen and thymus weight decreased generally in simazine-treated mice, while the weight of adrenal glands was higher than in the control. Simazine treatment (600 mg/kg) induced an increase in the percentage of CD4(+) cells in spleen and CD8 + in thymus. Simazine inhibited the IgM plaque-forming cell numbers and lowered the level of IgG and the proliferation of mitogen-stimulated B cells and T cells. In addition, splenic NK and peritoneal macrophage activities in exposed mice were significantly decreased. Exposure to simazine also decreased cytokine production by macrophages, such as interleukin-1 (IL-1), IL-6, and tumor necrosis factor-alpha (TNF-alpha). Taken together, data indicate that the immune system was suppressed by oral simazine exposure.     

Pulmonary inflammation in mice exposed to mainstream cigarette smoke

Male C57Bl/6 (C57) and ICR mice were exposed by nose-only inhalation to mainstream cigarette smoke (MS) from 2R4F reference cigarettes, at concentrations of 75, 250, and 600 microg of total particulate matter (TPM) per liter, for up to 6 mo. Respiratory-tract tissue (nose, larynx, and lung), blood, and bronchoalveolar lavage fluid (BALF) samples were collected and analyzed at several time points. Blood samples were analyzed for biomarkers of exposure (COHb and nicotine). BALF was analyzed for biomarkers of cell injury, inflammation, oxidative stress, enzyme activity, and cytokines. Blood COHb and plasma nicotine concentrations increased in a dose-dependent manner, confirming smoke exposure. Mild emphysema was observed following 28 wk of exposure. Macrophage accumulation and inflammatory infiltrates were observed around the alveolar ducts and adjacent vasculature. There was an approximately 13% increase in mean linear intercept (Lm) only in ICR mice exposed to 600 microg/L TPM. There were no significant changes in biomarkers of oxidative stress secondary to smoke exposures; however, 8-isoprostane significantly increased following the 13-wk post-inhalation period. BALF macrophage and neutrophil counts were rapidly and consistently elevated, while lymphocyte counts gradually increased over time. MS-induced inflammatory responses observed in this study are comparable to changes reported in chronic smokers, supporting the role of chronic inflammation in the pathogenesis of emphysema. However, mild emphysema in minimal numbers of mice suggests that MS exposure concentration and/or duration in the current study were not sufficient to induce a definitive emphysema phenotype.     

Evaluation of immune function in mice exposed to Ordram

The potential effects that the thiocarbamate herbicide Ordram has on the immune system of mice was evaluated following 12 days of acute dosing by oral gavage. Dosages of Ordram ranging from 20 to 320 mg/kg/day had no consistent significant effects on a variety of immune parameters investigated. The immune parameters measured were the following: body and lymphoid organ weights; splenic natural killer (NK) cell activity; lymphoproliferative responses to B and T lymphocyte mitogens and allogeneic spleen cells in a one-way mixed lymphocyte reaction; and delayed-type hypersensitivity and antibody responses to sheep red blood cells (SRBC). The effects that the immunosuppressant cyclophosphamide has on these immune parameters was also examined. The results indicate that Ordram does not appear to affect key parameters of the immune system of mice under the conditions of exposure employed.     

Neural tube defects in mice exposed to tap water

In May of 2006 we suddenly began to observe neural tube defects (NTDs) in embryos of untreated control mice. We hypothesized the mice were being exposed unknowingly to a teratogenic agent and investigated the cause. Our results suggested that NTDs were not resulting from bedding material, feed, strain, or source of the mice. Additionally, mice were negative for routine and comprehensive screens of pathogens. To further test whether the NTDs resulted from infectious or genetic cause localized to our facility, we obtained three strains of timed pregnant mice from commercial suppliers located in four different states. All strains and sources of mice arrived in our laboratory with NTDs, implying that commercially available mice were possibly exposed to a teratogen prior to purchase. Our investigation eventually concluded that exposure to tap water was causing the NTDs. The incidence of NTDs was greatest in purchased mice provided tap water and lowest in purchased mice provided distilled deionized water (DDI). Providing mice DDI water for two generations (F2‐DDI) eliminated the NTDs. When F2‐DDI mice were provided tap water from three different urban areas prior to breeding, their offspring again developed NTDs. Increased length of exposure to tap water significantly increased the incidence of NTDs. These results indicate that a contaminant in municipal tap water is likely causing NTDs in mice. The unknown teratogen appears to have a wide geographic distribution but has not yet been identified. Water analysis is currently underway to identify candidate contaminants that might be responsible for the malformations. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2011.     

Induction of alopecia in mice exposed to cigarette smoke

Besides being responsible for a high proportion of those chronic degenerative diseases that are the leading causes of death in the population, tobacco smoking has been associated with skin diseases. Smoke genotoxicants are metabolized in hair follicle cells, where they form DNA adducts and cause DNA damage. The suspicion was raised that, in humans, a link may exist between smoking and both premature grey hair and hair loss. In order to check this hypothesis, we carried out a study in C57BL/6 mice exposed whole-body to a mixture of sidestream and mainstream cigarette smoke. After 3 months exposure, most mice developed areas of alopecia and grey hair, while no such lesions occurred either in sham-exposed mice or in smoke-exposed mice receiving the chemopreventive agent N-acetylcysteine with drinking water. Cell apoptosis occurred massively in the hair bulbs at the edge of alopecia areas. Smoke-exposed mice had extensive atrophy of the epidermis, reduced thickness of the subcutaneous tissue, and scarcity of hair follicles. On the whole, exposure to smoke genotoxic components appears to alter the hair cycle with a dystrophic anagen pattern. Although this mechanism is different from that of genotoxic cytostatic drugs, N-acetylcysteine appears to exert protective effects in both conditions.     

Competitive NMDA receptor antagonists and agonists: effects on spontaneous alternation in mice exposed to cerebral oligemia

The purpose of the present study was to investigate the effects of competitive NMDA receptor antagonists,D,L-(E)-2-amino-4-methyl-5-phosphono-3-pentenoic acid (CGP 37849) and its ethyl ester (CGP 39551), or agonist, N-methyl-D-aspartate (NMDA) on spontaneous alternation in mice exposed to cerebral oligemia. Alternation behavior was evaluated in an Y-maze. Transient cerebral oligemic hypoxia was induced by bilateral clamping of carotid arteries (BCCA) for 30 min under pentobarbital anesthesia. In BCCA mice, CGP 37849 (5 mg/kg, ip) impaired spontaneous alternation when given 48 h or 7 days after surgery. CGP 39551 (5 mg/kg, ip) had no effect.NMDA (50 mg/kg, sc) improved performance of the task in BCCA mice when tested 48 h after surgery. These results suggest that cerebral oligemic hypoxia induced by BCCA leads to functional disturbances in the central nervous system, such as spontaneous alternation impairment and increased susceptibility to NMDA receptor-related drugs. Adverse potential of cerebral oligemia may limit a therapeutic use of NMDA receptor antagonists.