Gender differences in pulmonary inflammation following systemic cadmium administration in rats

Immunostimulatory and anti-inflammatory impact of Fragaria ananassa methanol extract in a rat model of cadmium chloride-induced pulmonary toxicity

Cadmium is an extremely dangerous heavy metal that can lead to disastrous consequences in all organisms. Several natural remedies reduce the toxicities of experimentally generated metals in animals. Strawberry Fragaria ananassa contains several bioactive compounds that may mitigate heavy-metal toxicity. The study aim was to evaluate the ability of a strawberry fruit methanol extract (SE) to reduce Cd toxicity and to identify and quantify the active constituents of SE. Forty Wistar rats were classified into four groups: the control group- 1 ml saline IP; SE group- 100 mg of SE/kg rats orally; cadmium (Cd) group-2 mg CdCl2/kg body weight/IP daily; and treated group- SE given 1 hour before Cd administration. Administration of Cd induced several histopathological and immunohistochemical alterations in lung sections. Biochemical analysis of lung homogenates and mRNA levels of antioxidants and inflammatory cytokines indicated significant changes to the risk profile. SE administration significantly decreased the oxidative stress, inflammation, tissue damage, the mean area percentage of collagen fibers, and positive immuno-expressions of TNF-α and NF-κB induced by CdCl2. Moreover, the MDA, TNF-α, GM-CSF, and IL-1β levels in Cd-exposed rat lung tissue were significantly lower in the SE-treated group than in the Cd-group. SE significantly augmented lung GSH, SOD, HO-1, GPx-2, and Nrf2 levels in Cd-exposed rats. SE mitigated Cd-caused oxidative stress and lung inflammation. Therefore, regularly consuming a strawberry-rich diet could benefit general health and help prevent and treat diseases.

Amelioration of silymarin against cadmium-induced toxicity in pregnant rats and their fetuses

BACKGROUND

Silymarin is an antioxidant without side effects even at relatively high physiological dosage. Therefore, it is safely used as a herbal medicine for treating different diseases.

AIM OF WORK

The purpose of this study was to examine the toxicity of cadmium (Cd) in pregnant rats and their fetuses and the ameliorative effects of silymarin (SL) against this toxicity.

MATERIALS & METHODS

A total of 24 pregnant rats allocated into four equal groups. Control, silymarin (200 mg/kg), Cd (5 mg/kg), and a combination of Cd and silymarin concurrent from 6 to 20th gestational day. Number of corpora lutea, dams', gravid uteri, placental weights, and likewise fetal body weights and lengths were analyzed as physical parameters. Serum levels of aspartate transaminase, alanine transaminase, creatinine, urea, uric acid, and maternal and fetal liver tissues for malondialdehyde, superoxide dismutase, catalase and glutathione activity were studied. The histology of hepatic and renal tissues for both mothers and fetuses was examined. Data were statistically analyzed by analysis of variance test and Duncan's multiple range test was used to compare group means.

RESULTS

The findings evidenced that Cd causes teratogenic abnormalities and histopathological variation in hepatic and renal tissues of both mothers and fetuses. Cd triggers oxidative stress and disrupts liver and kidney function. In Cd + silymarin treated rats exhibited improvement in the pregnancy outcomes, reduced histopathological changes, oxidative stress as well as liver and kidney enzymes.

CONCLUSION

We deduced that using of silymarin during gestation is effective and ameliorate the toxic maternal complications caused by cadmium.

Sex-dependent vascular effects of cadmium sub-chronic exposure on rats

Cadmium exposure is related to several cardiovascular diseases, such as hypertension, atherosclerosis and endothelial dysfunction. However, the toxic effect of cadmium can be dependent on the sex when examined sex in experimental models. The aim of this study was to analyze the effects of cadmium exposure on the cardiovascular system of male and female rodents. The experiments were carried out on both-sexes Wistar at 4 months of age, where from 3 months onwards, cadmium (CdCl2 100 mg/l in placed the drinking water for 30 days) or vehicle delivered (distilled water) was ingested. Before and after 30 days of exposure to cadmium, systolic blood pressure was regularly measured. After exposure, blood was collected to measure dosage of cadmium, in male and female, and estrogen in females. Vascular reactivity to phenylephrine (Phe), acetylcholine (ACh), and sodium nitroprusside (SNP) was studied at respective isolated aortic segments. After the period to Cd-exposure, systolic blood pressure was increased only in the male rats. Males also had higher levels of plasma cadmium than those of female rats, and exposure to the metal did not affect the amount of estrogen produced in the female rats. Increased myeloperoxidase (MPO) activity was also observed in both the males and females that had been exposed to the metal. Moreover, exposure to the cadmium reduced the ACh relaxation and increased vascular reactivity to Phe, resulting in an imbalance between nitric oxide superoxide anion in the isolated aorta of male rats. In female rats, sub-chronic cadmium exposure did not modify the vascular reactivity to Phe and neither to the ACh. The present study revealed that the Cd exposure for 30 days induced sex-dependent cardiovascular abnormalities.

Estradiol resolves pneumonia via ERβ in regulatory T cells

Current treatments for pneumonia (PNA) are focused on the pathogens. Mortality from PNA-induced acute lung injury (PNA-ALI) remains high, underscoring the need for additional therapeutic targets. Clinical and experimental evidence exists for potential sex differences in PNA survival, with males having higher mortality. In a model of severe pneumococcal PNA, when compared with male mice, age-matched female mice exhibited enhanced resolution characterized by decreased alveolar and lung inflammation and increased numbers of Tregs. Recognizing the critical role of Tregs in lung injury resolution, we evaluated whether improved outcomes in female mice were due to estradiol (E2) effects on Treg biology. E2 promoted a Treg-suppressive phenotype in vitro and resolution of PNA in vivo. Systemic rescue administration of E2 promoted resolution of PNA in male mice independent of lung bacterial clearance. E2 augmented Treg expression of Foxp3, CD25, and GATA3, an effect that required ERβ, and not ERα, signaling. Importantly, the in vivo therapeutic effects of E2 were lost in Treg-depleted mice (Foxp3^DTR mice). Adoptive transfer of ex vivo E2-treated Tregs rescued Streptococcuspneumoniae–induce PNA-ALI, a salutary effect that required Treg ERβ expression. E2/ERβ was required for Tregs to control macrophage proinflammatory responses. Our findings support the therapeutic role for E2 in promoting resolution of lung inflammation after PNA via ERβ Tregs.

Cadmium and immunologically-mediated homeostasis of anatomical barrier tissues

Cadmium (Cd) is a toxic heavy metal that when absorbed into the body causes nephrotoxicity and effects in other tissues.Anatomical barrier tissues are tissues that prevent the entry of pathogens and include skin, mucus membranes and the immune system. The adverse effects of Cd-induced immune cell's activity are the most extensively studied in the kidneys and the liver. There are though fewer data relating the effect of this metal on the other tissues, particularly in those in which cells of the immune system form local circuits of tissue defense, maintaining immune-mediated homeostasis. In this work, data on the direct and indirect effects of Cd on anatomical barrier tissue of inner and outer body surfaces (the lungs, gut, reproductive organs, and skin) were summarized.

Protective Effects of Fragaria ananassa Extract Against Cadmium Chloride-Induced Acute Renal Toxicity in Rats

For experiments of cadmium toxicity in animal models, cadmium (II) chloride is often used due to its solubility in water and its ability to produce high concentrations of cadmium at the target site. The present study was designed to investigate the potential inhibitory effect of the Fragaria ananassa fruit extract on cadmium (II) chloride-induced renal toxicity in rats. Tested animals were pretreated with the extract of F. ananassa and injected with cadmium (II) chloride (6.5-mg/kg body weight) for 5 days. Cadmium (II) chloride significantly increased kidney cadmium concentration, kidney weight, lipid peroxidation, and nitric oxide production. Plasma uric acid, urea, and creatinine levels also increased significantly, indicative of kidney dysfunction. These effects were accompanied by significantly decreased levels of nonenzymatic and enzymatic antioxidant molecules (i.e., glutathione content and the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase). Moreover, messenger RNA (mRNA) expression of the antiapoptotic protein, Bcl-2, and the antioxidant proteins, superoxide dismutase 2 and glutathione reductase, were downregulated markedly, whereas mRNA expression of tumor necrosis factor-α was upregulated significantly in kidney tissues of cadmium-treated rats. Histology of kidney tissue demonstrated severe, adverse changes that reflected cadmium-induced tissue damage. Pretreatment of rats with the extract of F. ananassa ameliorated all aforementioned cadmium (II) chloride-induced changes. In conclusion, the present study showed acute renal toxicity in rats treated with cadmium (II) chloride. The study also revealed that pretreatment with the extract of F. ananassa could protect the kidney against cadmium (II) chloride-induced acute renal toxicity.

Chronic Low-Dose Cadmium Exposure Impairs Cutaneous Wound Healing With Defective Early Inflammatory Responses After Skin Injury

Impairment of the immune system is a developing concern in evaluating the toxicity of cadmium (Cd). In the present study, we investigated if Cd could impair cutaneous wound healing through interfering with inflammation after injury. We found that exposure of mice to CdCl2 through drinking water at doses of 10, 30, and 50 mg/l for 8 weeks significantly impaired cutaneous wound healing. Chronic 30 mg/l CdCl2 treatment elevated murine blood Cd level comparable to that of low dose Cd-exposed humans, had no effect on blood total and differential leukocyte counts, but reduced neutrophil infiltration, chemokines (CXCL1 and CXCL2), and proinflammatory cytokines (TNFα, IL-1β, and IL-6) expression in wounded tissue at early stage after injury. Wounded tissue homogenates from CdCl2-treated mice had lower chemotactic activity for neutrophils than those from untreated mice. Mechanistic studies showed that chronic Cd treatment suppressed ERK1/2 and NF-κB p65 phosphorylation in wounded tissue at early stage after injury. Compared with neutrophils isolated from untreated mice, neutrophils from CdCl2 treated mice and normal neutrophils treated with CdCl2 invitro both had lower chemotactic response, calcium mobilization and ERK1/2 phosphorylation upon chemoattractant stimulation. Collectively, our study indicate that chronic low-dose Cd exposure impaired cutaneous wound healing by reducing neutrophil infiltration through inhibiting chemokine expression and neutrophil chemotactic response, and suppressing proinflammatory cytokine expression. Cd may suppress chemokine and proinflammatory expression through inactivating ERK1/2 and NF-κB, and inhibit neutrophil chemotaxis by attenuating calcium mobilization and ERK1/2 phosphorylation in response to chemoattractants.

Protective effect of Fragaria ananassa methanolic extract on cadmium chloride (CdCl2)-induced hepatotoxicity in rats

This study investigated the protective effect of Fragaria ananassa methanolic extract on cadmium chloride (CdCl₂)-induced hepatotoxicity in rats. CdCl₂ was intraperitoneally injected at a dose of 6.5 mg/kg of body weight for 5 d with or without methanol extract of Fragaria ananassa (250 mg/kg). The hepatic cadmium concentration, lipid peroxidation, nitric oxide, glutathione (GSH) content, and antioxidant enzyme activities, including superoxide dismutase, catalase (CAT), GSH peroxidase, and GSH reductase, were estimated. CdCl₂ injection induced a significant elevation in cadmium concentration, lipid peroxidation, and nitric oxide and caused a significant depletion in GSH content compared to controls, along with a remarkable decrease in antioxidant enzymes. Oxidative stress induction and cadmium accumulation in the liver were successfully ameliorated by F. ananassa (strawberry) pre-administration. In addition, the pre-administration of strawberry decreased the elevated gene expression of the pro-apoptotic Bax gene as well as the protein expression of caspases-3 in the liver of CdCl₂-injected rats. In addition, the reduced gene expression of anti-apoptotic Bcl-2 was increased. Our results show an increase in the expression of tumor necrosis factor α in the liver of rats treated with cadmium. In sum, our results suggested that F. ananassa successfully prevented deleterious effects on liver function by reinforcing the antioxidant defense system, inhibiting oxidative stress and reducing apoptosis.

Effect of Cadmium on Trophoblast Cell Proliferation and Apoptosis in Different Gestation Periods of Rat Placenta

In this study, we aimed to show how cadmium (Cd) affects the trophoblast proliferation and differentiation in the placenta and the apoptotic activity in different gestational days and, hence, its effects of placental development with immunohistochemical and TUNEL techniques. Experimental model of our study consisted of placental development of control and Cd groups on 15, 17, 19, and 21th days of the gestation. Female rats in Cd groups were subcutaneously administered a single dose of 0.5 mg Cd/kg/day dissolved in sodium chloride as 2 mL/kg Cd chloride until the day they sacrificed. Embryo and placenta of female rats were separately removed on 15, 17, 19, and 21th days of the gestation in which the placental development takes place and placentas were processed for microscopic examinations. In the placentas of the control group, all layers were observed to be formed on the 15th gestational day and thereafter a continuous growth was monitored. In the Cd group also all layers existed from the 15th gestational day. However, they were smaller in size than control groups. Frequency of proliferating cell nuclear antigen (PCNA)-positive cells was decreased and the number of apoptotic cells was increased in all the gestational days related to Cd. In conclusion, Cd administered during the pregnancy was observed to cause abnormal placental development by disrupting the normal structure of the placenta, inhibiting the proliferation of trophoblast and increasing the number of apoptotic trophoblast cells.

Effect of a single dose of cadmium on pregnant Wistar rats and their offspring

Cadmium (Cd) is a well-known toxicant targeting many organs, among them placenta. This heavy metal also has embryonary and foetal toxicity. This study was undertaken to analyse the effect of a single Cd dose administered at 4, 7, 10 or 15 days of gestation on the offspring of pregnant rats sacrificed at 20 days of gestation. Cadmium chloride was administered subcutaneously at 10 mg/kg body weight to Wistar pregnant dams; control animals received a proportionate volume of sterile normal saline by the same route. Maternal uteri, livers, kidneys and lungs, and foetuses were examined at necropsy. Samples of maternal organs and whole foetuses were collected for histopathologic examination, determination of Cd levels and staining by the Alizarin red S technique. Results revealed a clear embryotoxic and a teratogenic effect of this heavy metal, the former as a significant increase in the number of resorptions, and the latter as significant decrease of the gestational sac weight, and the size and weight of foetuses of Cd-treated dams as well as induced malformations in skull bones, vertebrae and thoracic, and pelvian limbs. The deleterious effects found were similar to those previously reported for other animal models suggesting a high conservation of the pathogenic mechanisms of Cd. Additionally, many of the addressed aspects showed a slight dependence on the time of administration of the toxic that might be due to the accumulation of the metal in different organs, as we were able to demonstrate by the analysis of its concentration.

Short-term inhalation of cadmium oxide nanoparticles alters pulmonary dynamics associated with lung injury, inflammation, and repair in a mouse model

CONTEXT

Cadmium oxide nanoparticles (CdO NPs) are employed in optoelectronic devices and as a starting material for generating quantum dots as well as for medical imaging and targeting of pharmaceutical agents to disease sites. However, there are lack of data concerning short- and long-term effects of CdO NPs on the lungs.

OBJECTIVE

To determine the effects of inhaled CdO NPs at an occupationally relevant concentration on pulmonary injury and repair, and on systemic immunity in adult male mice.

METHODS

Mice were exposed to 240 μg CdO NPs/m(3) for seven days (3 h/d) and lavage levels of pulmonary injury/inflammatory markers, bacterial uptake by circulating phagocytes, and lung histology examined either one or seven days following the final exposure.

RESULTS

Levels of total protein, lactate dehydrogenase activity, cytokine markers of inflammation (i.e. interleukin-1β, tumor necrosis factor-α, and interferon-γ), tissue remodeling matrix metalloproteinases (MMP)-2 and -9 activity, and phagocytic activity of circulating phagocytes were significantly increased one day after the final exposure. By seven days post-exposure, MMP-2 activity decreased to control levels, while MMP-9 activity remained significantly above control values, although dropping by about half from day one.

CONCLUSIONS

This study demonstrates that short-term inhalation exposure to CdO NPs can stimulate pathways in the lungs associated with inflammation, cell injury, and tissue remodeling as well as alter immune function. Findings here demonstrate that even short-term inhalation exposure to CdO NPs in the workplace could lead to deleterious pulmonary effects in exposed workers.

Blood cadmium levels are associated with a decline in lung function in males

BACKGROUND

Cadmium exposure was found to cause a decline in lung function among the general population, but these findings were limited to smokers and gender differences were not explored.

OBJECTIVES

To examine the relationship between cadmium and chronic obstructive pulmonary disease (COPD) according to gender and smoking status in Korea.

METHODS

Cross-sectional data from the Korean National Health and Nutrition Examination Survey from 2008 to 2011 were analyzed. COPD was defined by a pre-bronchodilator forced expiratory volume in 1s divided by forced vital capacity of <0.70. A logistic regression model was used to elucidate the association between blood cadmium levels and COPD according to gender and smoking status.

RESULTS

Among 3861 eligible participants, 3622 were included in the analysis. The prevalence of COPD demonstrated an increasing trend in males (P for trend<0.001), but not in females (P for trend=0.67). After adjusting for covariates, a higher blood cadmium level, but within the normal range, was associated with COPD in males, including those who had never-smoked (P for trend <0.001 and P for trend=0.008). However, a higher blood cadmium level was not significantly associated with COPD in females, including those who had never smoked (P for trend=0.39 and P for trend=0.43).

CONCLUSIONS

A higher blood cadmium level, within the normal range, was associated with COPD in males, including those who had never smoked. However, there was no significant association between blood cadmium levels and COPD in females.

An O2-sensitive glomus cell-stem cell synapse induces carotid body growth in chronic hypoxia

Neural stem cells (NSCs) exist in germinal centers of the adult brain and in the carotid body (CB), an oxygen-sensing organ that grows under chronic hypoxemia. How stem cell lineage differentiation into mature glomus cells is coupled with changes in physiological demand is poorly understood. Here, we show that hypoxia does not affect CB NSC proliferation directly. Rather, mature glomus cells expressing endothelin-1, the O2-sensing elements in the CB that secrete neurotransmitters in response to hypoxia, establish abundant synaptic-like contacts with stem cells, which express endothelin receptors, and instruct their growth. Inhibition of glomus cell transmitter release or their selective destruction markedly diminishes CB cell growth during hypoxia, showing that CB NSCs are under the direct "synaptic" control of the mature O2-sensitive cells. Thus, glomus cells not only acutely activate the respiratory center but also induce NSC-dependent CB hypertrophy necessary for acclimatization to chronic hypoxemia.

Differential effects of cadmium administration on peripheral blood granulocytes in rats

Infiltration of circulatory inflammatory cells is a common histopathological finding in target organs following cadmium administration, but there is paucity of data concerning their activity. In this study, the effects of sublethal (1 mg/kg) cadmium on peripheral blood polymorphonuclear (PMN) cells were examined 48 h following administration in rats, when tissue (liver and lung) infiltration of these cells was observed. Cadmium administration resulted in systemic inflammatory cytokine and acute phase response with an increase in circulatory neutrophil numbers and cells that express CD11b molecules. Rise in basic aspects of oxidative activity including intracellular myeloperoxidase (MPO), reactive oxygen (nitroblue tetrazolium/NBT cytochemical assay) and nitrogen (Griess assay) species production was observed in PMNs from cadmium-administered rats. A decrease in levels of mRNA for IL-1β, TNF-α and IL-6 was noted, but production of these cytokines was affected differentially. Described effects of cadmium on PMNs add further to the understanding of inflammatory potential of this environmental contaminant.

Actin cytoskeleton redox proteome oxidation by cadmium

Epidemiological studies associate environmental cadmium (Cd) exposure with the risk of lung diseases. Although mechanisms are not fully elucidated, several studies demonstrate Cd effects on actin and actin-associated proteins. In a recent study of Cd at concentrations similar to environmental exposures, we found that redox-dependent inflammatory signaling by NF-κB was sensitive to the actin-disrupting agent, cytochalasin D. The goal of the present study was to use mass spectrometry-based redox proteomics to investigate Cd effects on the actin cytoskeleton proteome and related functional pathways in lung cells at low environmental concentrations. The results showed that Cd under conditions that did not alter total protein thiols or glutathione redox state caused significant oxidation of peptidyl Cys of proteins regulating actin cytoskeleton. Immunofluorescence microscopy of lung fibroblasts and pulmonary artery endothelial cells showed that low-dose Cd exposure stimulated filamentous actin formation and nuclear localization of destrin, an actin-depolymerizing factor. Taken together, the results show that redox states of peptidyl Cys in proteins associated with actin cytoskeleton pathways are selectively oxidized in lung by Cd at levels thought to occur from environmental exposure.

Long-lasting oxidative pulmonary insult in rat after intratracheal instillation of silica nanoparticles doped with cadmium

Silica/cadmium containing nanomaterials are now produced on industrial scale due to their potential for a variety of technological applications. Nevertheless, information on toxicity, exposure and health impact of these nanomaterials is still limited. In this study, in vivo effects of silica nanoparticles (SiNPs) doped with Cd (SiNPs-Cd, 1mg/rat), soluble CdCl(2) (400 μg/rat), or SiNPs (600 μg/rat) have been investigated by evaluating F(2)-isoprostanes (F(2)-IsoPs), superoxide dismutase (SOD1), inducible nitric oxide synthase (iNOS) and cyclooxygenase type 2 (COX-2) enzymes, as markers of oxidative stress, 24h, 7 and 30 days after intra-tracheal (i.t.) instillation to rats. Free and esterified F(2)-IsoPs were evaluated in lung and plasma samples by GC/NICI-MS/MS analysis, and SOD1, iNOS and COX-2 expression in pulmonary tissue by immunocytochemistry. Thirty days after exposure, pulmonary total F(2)-IsoPs were increased by 56% and 43% in CdCl(2) and SiNPs-Cd groups, respectively, compared to controls (32.8 ± 7.8 ng/g). Parallel elevation of free F(2)-IsoPs was observed in plasma samples (by 113% and 95% in CdCl(2) and SiNPs-Cd groups, respectively), compared to controls (28 ± 8 pg/ml). These effects were already detectable at day 7 and lasted until day 30 post-exposure. Pulmonary SOD1-, iNOS-, and COX-2-immunoreactivity was significantly enhanced in a time-dependent manner (7 days <30 days) after both CdCl(2) and SiNPs-Cd treatments. SiNPs did not influence any of the evaluated endpoints. The results indicate the capacity of engineered SiNPs-Cd to cause long-lasting oxidative tissue injury following pulmonary exposure in rat.

Effects of dietary cadmium exposure on osmoregulation and urine concentration mechanisms of the semi-desert rodent Meriones shawi

Contamination by cadmium in the environment is of great concern because of its toxicity and threats to human and animal health. The current study was conducted to investigate the effects of a cadmium contaminated diet on the osmoregulation and urine concentration mechanisms of the semi-desert rodent Meriones shawi and eventual accumulation of this metal in vital organs such as the kidneys, which are directly implicated in water regulation. Originally, we used Differential Pulse Anodic Stripping Voltammetry (DPASV) to avoid the matrix interference due to the highly organic content in the biological samples. Our results show that Meriones shawi successfully maintained a homeostasis state and presented a special adaptation to regulate urine volume during cadmium exposure by decreasing diuresis and increasing urinary osmolality. The plasma osmolality and hematocrit remained constant throughout the experiment. The stripping signals of cadmium are linear up to 0.3-100 μg L(-1) range, with a detection limit of 0.28 μg L(-1). The DPASV technique was useful for easy, fast, selective and sensitive determination of Cd, which permits working at cellular concentration. This gives us more information about the chemical form in which Cd is introduced into the organ, as well as the intracellular Cd quantities. This study has potential importance if this valuable novel animal model, imitating human and animal environmental chronic exposure to Cd, could serve as an appropriate terrestrial biomonitor for Cd contaminated sites. These results are encouraging in the context of developing a low-cost and fast technology for the detection of pollutants and for studying the impairment caused by their effects.