Toxic effect in the lungs of rats after inhalation exposure to benzalkonium chloride.

BACKGROUND: Benzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) toxic to microorganisms. Inhalation is one of the major possible routes of human exposure to BAC. MATERIALS AND METHODS: Experiments were performed on female Wistar rats. The rats were exposed to aerosol of BAC water solution at the target concentration of 0 (control group) and 35 mg/m(3) for 5 days (6 h/day) and, after a 2-week interval, the animals were challenged (day 21) with BAC aerosol at the target concentration of 0 (control group) and 35 mg/m3 for 6 h. RESULTS: Compared to the controls, the animals exposed to BAC aerosol were characterized by lower food intake and their body weight was significantly smaller. As regards BAC-exposed group, a significant increase was noted in relative lung mass, total protein concentration, and MIP-2 in BALF both directly after the termination of the exposure and 18 h afterwards. Significantly higher IL-6 and IgE concentrations in BALF and a decrease in the CC16 concentration in BALF were found in the exposed group immediately after the exposure. The leukocyte count in BALF was significantly higher in the animals exposed to BAC aerosol compared to the controls. In the lungs of rats exposed to BAC the following effects were observed: minimal perivascular, interstitial edema, focal aggregates of alveolar macrophages, interstitial mononuclear cell infiltrations, thickened alveolar septa and marginal lipoproteinosis. CONCLUSION: Inhalation of BAC induced a strong inflammatory response and a damage to the blood-air barrier. Reduced concentrations of CC16, which is an immunosuppressive and anti-inflammatory protein, in combination with increased IgE concentrations in BALF may be indicative of the immuno-inflammatory response in the animals exposed to BAC aerosol by inhalation. Histopathological examinations of tissue samples from the BAC-exposed rats revealed a number of pathological changes found only in the lungs.

Neutrophil function and apoptosis in patients with chronic hepatitis C treated with pegylated interferon α and ribavirin.

The role of neutrophils in the pathogenesis of chronic hepatitis C as well as the effect of pegylated interferon α (PEG-IFN-α) and ribavirin treatment on neutrophil function is not precisely known. The study included 32 patients with CCH aged between 19 and 58 years (mean 33.5 years). Before and after 12 weeks of treatment with Peg-IFN-α and ribavirin, intracellular reactive oxygen species (ROS) level, expression of adhesion molecules CD11b/MAC-1, CD16, CD18 and CD62L on neutrophils, as well as apoptosis and necrosis of these cells were analyzed with the use of flow cytometry. During antiviral therapy, a statistically significant decrease of mean fluorescence intensity for CD16 high and CD62 and increase for CD11b/MAC-1 along with the increased apoptosis and decreased necrosis of neutrophils were observed. After 12 weeks of treatment, intracellular ROS production by unstimulated neutrophils did not change, but after stimulation with phorbol 12-myristate 13-acetate, statistically significant increase of ROS level was observed. During PEG-IFN-α and ribavirin treatment, activation of neutrophil function and increased ROS production were reported, which possibly resulted in accelerated apoptosis of these cells.

The inflammatory response in lungs of rats exposed on the airborne particles collected during different seasons in four European cities.

Epidemiological studies have reported associations of ambient particulate air pollution, especially particulate matter (PM) less than 10 µm with exacerbations of asthma and chronic obstructive pulmonary disease. In an in vivo model, we have tested the toxicity of urban airborne particles collected during spring, summer, and winter seasons in four cities (Amsterdam, Lodz, Oslo, and Rome) spread across Europe. The seasonal differences in inflammatory responses were striking, and almost all the study parameters were affected by PM. Coarse fractions of the urban particle samples were less potent per unit mass than the fine fractions in increasing cytokine [macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)-α] levels and in reducing Clara-cell secretory protein (CC16) levels. This study shows that PM collected at 4 contrasting sites across Europe and during different seasons have differences in toxic potency. These differences were even more prominent between the fine and coarse fractions of the PM.

Expression of Th1/Th2/Th3/Th17-related genes in recurrent aphthous ulcers.

The pathogenesis of recurrent aphthous ulceration (RAU) is unknown, although an abnormal immune reaction appears to be involved. RAU may result from oral epithelium damage caused by T cell-mediated immune response. To improve understanding of the role of T cells in RAU, the present study analyzed. the expression of T cell-related genes in oral ulcers from patients with RAU, as well as in healthy non-keratinized oral mucosa from aphthae-free volunteers. Biopsies from RAU patients and healthy individuals were analyzed using Human Th1-Th2-Th3 RT(2) Profiler PCR Array and qRT-PCR that allowed to quantify the transcript levels of 86 genes related to T cell activation. We found that cells present in aphthous ulcers express a characteristic Th1-like gene profile. The majority of genes up-regulated in aphthous lesions such as IFN-γ, TNF, IL-15, IRF1, STAT-1 and STAT-4 were Th1-associated. Th2-realated genes were not overexpressed in RAU tissues, with the exception for CCR3. Th3- and Th17-related gene expression patterns were not demonstrated in RAU. These findings clearly reveal that aphthous ulcer formation is predominantly dependent on the activation of the Th1-type immune response.

Perinatal exposure of mice to TCDD decreases allergic sensitisation through inhibition of IL-4 production rather than T regulatory cell-mediated suppression.

OBJECTIVE: The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a widespread, man-made, persistent organic pollutant with high immunotoxic potentials. It suppresses cell-mediated and humoral immune responses through mechanisms dependent on aryl-hydrocarbon receptor expression and immunosuppressive activity of the cells. Most sensitive to TCDD are organisms during fetal and infant life, mostly due to the developmental stage of many biological systems of the host, including immune system. Recent data show that T regulatory cells that have the potential to suppress immune reactions and which develop after TCDD exposure are also responsible for protection from allergy development. Our goal was to investigate if perinatal exposure to TCDD can affect allergic sensitisation and if T reg cells participate in this phenomenon. MATERIALS AND METHODS: Mice, Balb/c, were perinatally exposed to TCDD or to the carrier. Six weeks old control or exposed mice were sensitised with ovalbumin. Spleen cells of the animals were used to assess the content of T reg cells by means of flow cytometry. Levels of cytokines were assessed by ELISA technique in supernatants of the cells stimulated with anti-CD3 antibody. As a measure of sensitisation, total IgE and anti-OVA IgE were measured in serum of mice by ELISA method. To assess the function of T reg cells isolated from OVA-sensitised control or TCDD exposed animals we performed transfer studies. RESULTS: Here we show that perinatal exposure to TCDD decreases allergic sensitisation and that this process is related to inhibition of IL-4 synthesis rather than suppression mediated by T regulatory cells. CONCLUSION: We hypothesise that dioxin exposure can be an important environmental modulator of immunological responses that participate in allergic reactions.

Comparative studies of lymph node cell subpopulations and cytokine expression in murine model for testing the potentials of chemicals to induce respiratory sensitization.

OBJECTIVES: To investigate immunological changes in lymph nodes based on expression of cell-specific receptors and cytokine expression profile and accompanying inflammatory reactions in lungs of mice treated with chemicals of known potentials to induce respiratory sensitization and those in which activity in this regard is unclear. MATERIALS AND METHODS: On day 1 and 7, Balb/c mice received toluene-2,4-diisocyanate (TDI), trimellitic anhydride (TMA), 1-chloro-2,4-dinitrobenzene (DNCB), glutaraldehyde (GA), formaldehyde (FA), benzalkonium chloride (ChB) or vehicle. On day 14, they received a single intranasal instillation with the same chemical or vehicle. On day 15, auricular lymph nodes (LN) were excised and used for analyzes of T-, B-cells, expression of CD44 and for the estimation of IL-4 and IFN-gamma production after in vitro stimulation with concanavalin A (ConA) and also for IL-4 and IFN-gamma mRNA expression analyses using Real-Time PCR. Inflammatory changes in lungs were observed by estimation of TNF-alpha and MIP-2 concentrations and cell numbers and their type in BAL. RESULTS: There were no significant changes in cell subpopulations of T helper cells in LN. The percent of B cells was significantly increased after treatment with DNCB, TDI, and GA. Increased expression of CD44 on T cells was also observed. Both IL-4 and IFN-gamma were found increased in TDI- and FA-treated mice, while only IL-4 was increased in TMA-treated mice. Real-Time PCR analyses, however, showed increased IL-4 mRNA expression for TDI- and TMA-, and IFN-gamma mRNA expression for DNCB-treated mice. We haven't observed significant changes in inflammatory reactions in the lungs of exposed animals. CONCLUSIONS: Studying immunological changes with first determining the activation status of T cells followed by analyzes of expression of mRNA for Th1 and Th2 cytokines in murine model could be a useful method for assessment of the potentials of chemicals to induce respiratory sensitization but is not sufficient. Addition of ventilatory measurements, but not necessarily inflammatory reactions, could complete the model.

Pulmonary irritation after inhalation exposure to benzalkonium chloride in rats.

BACKGROUND: Benzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) with a C8 to C18 chain length of alkyl groups. Since BAC exerts toxic effects on microorganisms, it has been used as an effective germicide and preservative, mostly in cosmetic industry and medicine. However, the toxic potential of BAC may be hazardous to humans, due to the common use of preparations containing BAC as a preservative. MATERIAL AND METHODS: To assess the possible toxic effects of BAC, two-stage experiments were performed on female Wistar rats. At first, LC50 after a single exposure to BAC aerosol was determined. Then, the animals were exposed to BAC aerosol at 30 mg/m3 for 6 h, and for 3 days (6 h/day). The controls were unexposed rats. Directly after BAC exposure and 18 h afterwards, BALF concentrations were measured of total protein, Clara cell protein, matrix metalloproteinase-9 (MMP-9), hyaluronic acid (HA), immunoglobulin E (IgE) and cytokines (TF-alpha, IL-6 and MIP-20), lactate dehydrogenase (LDH) and GSH-S-transferase (GST). RESULTS: The LC50 value for exposed rats was ca. 53 mg BAC in m3 air for 4 h. All the rats survived single and repeated inhalation exposure to 30 mg/m3 BAC. After single and repeated exposure, lung weight, total protein, HA and LDH activity in BALF of exposed rats were higher than in controls while CC16 levels were decreased. A significantly higher BALF concentration of IL-6 and IgE was noted in animals exposed to single and repeated doses. BALF concentrations of MMP-9, TNF-alpha, and MIP-2 in exposed rats were similar to those in control animals. CONCLUSION: BAC may be classified to class I acute inhalation toxicity. It showed a strong inflammatory and irritant activity on the lungs after 6h inhalation and stimulated dynamic patterns of IL-6 and IgE production and protein infiltration from blood vessels to BALF. Continued exposure resulted in cellular destruction, a statistically significant increase in LDH activity and a continuous decrease in CC16 concentration in BALF.

Exposure to chlorphenvinphos, an organophosphate insecticide, prevents from behavioral sensitization to amphetamine.

OBJECTIVES: Exposure to organophosphorus (OP) pesticides, irreversible inhibitors of acetylcholinesterase (AChE), may result in long-lasting alterations in the functional state of the central nervous system. In earlier studies, we found that a single exposure of the rat to chlorphenvinphos (CVP), an OP pesticide, made the animal hyposensitive to amphetamine (AMPH) three weeks posttreatment. A repeated administration of AMPH is known to result in a progressive increase in the behavioral sensitivity to the psychostimulant. It makes it likely that treatment with AMPH after the CVP exposure may result in amelioration of the CVP-induced hyposensitivity to the psychostymulant. The purpose of the present experiment was to check out this supposition. MATERIALS AND METHODS: At the first stage, the relationship between the CVP dose and the effect on sensitivity to AMPH was tested. The rats were given CVP once intraperitoneally (i.p.) at a dose of 0.0, 1.0 or 3.0 mg/kg. Three weeks later their open field behavior was assessed before and after i.p. administration of 0.25, 0.5 or 1.0 mg/kg of AMPH. At the subsequent stage, the susceptibility of the CVP-treated rats to AMPH sensitization by repeated AMPH treatment was investigated. For this purpose each of the rats was repeatedly treated with AMPH in its home cage (one injection/day for five days). At stage two, the daily AMPH dose received by each animal was of the same magnitude as that received at stage one. Two weeks after the last AMPH treatment dose, the motor response to a test AMPH dose (0.5 mg/kg) was measured in all rats. RESULTS: The results of stage one confirmed a significant reduction of behavioral sensitivity to AMPH in the CVP-treated rats. The results of stage two indicated that the CVP-induced decrease in sensitivity to AMPH was not ameliorated by a repeated treatment with AMPH at any of the used doses. In fact, in the rats exposed to the high CVP dose, repeated treatment with AMPH resulted, dose dependently, in augmenting of the depressive effect of the pesticide. CONCLUSIONS: It appears then that treatment to an OP pesticide reduces the rat's sensitivity to AMPH and makes the animal resistant to sensitization by repeated treatment with the psychostimulant.

The Leiden mutation and activated protein C resistance as risk factors for disseminated intravascular coagulation in acutely poisoned patients.

The aim of this work was to assess the prevalence of a genetic predisposition to disseminated intravascular coagulation (DIC) among acutely poisoned patients. Activated protein C resistence (APCR) is a genetically determined cause of thrombophilia and DIC development. One hundred seventy-six subjects were divided into three groups: one consisted of 83 acutely poisoned patients with DIC; a second consisted of 57 acutely poisoned patients without DIC; the third group consisted of 91 healthy controls. Abnormal results of APCR testing were found in 24.1% of the poisoned DIC group, 5.3% of the poisoned nonDIC group, and 3.3% of the control group. Genetic tests were performed in 37 selected patients. Factor V Leiden mutation (G/A genotype) was determined to be present in people whose R index value was below 1.9. These results raise the possibility that outcomes of acute poisonings may be influenced by genetic predisposition.

Amphetamine- and scopolamine-induced locomotor activity following treatment with chlorphenvinphos or chlorphyriphos in rats.

OBJECTIVES: Effects of acute exposure to organophosphorous pesticides (OPs), chlorphenvinphos (CVP) or chlorphyriphos (CPF) on amphetamine (AMPH)- or scopolamine (SCOP)-induced open-field locomotion were compared in rats. MATERIALS AND METHODS: CVP and CPF were administered intraperitoneally, both at doses resulting in about 50% inhibition of erythrocyte acetylcholinesterase (rbcAChE). The pesticide groups did not differ one from another in the magnitude of the acute behavioral effects. RESULTS: Three weeks after the exposure, i.e. when AChE activity returned to normal level, the behavioral response to AMPH and SCOP was significantly reduced in CVP-, but not in CPF-pretreated rats. CONCLUSIONS: These results confirm that a single exposure to organophosphorous pesticides may result in neurobehavioral effects detectable after restitution of AChE. They also show that CVP and CPF differ in respect of long lasting functional consequences of exposure, which suggests a difference in the mechanism of toxicity.

Pretreatment with footshock alters some effects of subsequent organophosphate exposure.

Pre-exposure to non-chemical stressors may alter a subject's vulnerability to chemical stressors. We found recently that rats given a subtoxic dose of chlorfenvinphos (CVP), an organophosphorus pesticide, develop behavioral hyposensitivity to amphetamine (AMPH). The present experiments were performed in order to find out whether pre-exposure to a non-chemical stressor several days prior to CVP exposure could influence this effect of the pesticide. In experiment 1 adult male Wistar rats were subjected once to either a short, 5 min (SFS) or long, 20 min (LFS) series of unavoidable footshocks (FS). Twenty-four hours or 14 days after the FS, their open field behavior was tested before and after a test dose of AMPH (0.5 mg/kg. i.p). In experiment 2, the rats were subjected to LFS and 14 days later they were injected intraperitoneally with CVP (1.0 mg/kg) or vehicle (corn oil). In both experiments, serum corticosterone (CORT) levels were determined in separate groups of rats in order to assess the magnitude of the stress response induced by the applied stressors. It was found that: (i) the rise in serum CORT concentration after SFS or LFS was similar in magnitude, while that following LFS was more persistent; (ii) exposure to LFS, but not to SFS, resulted in a decreased response to AMPH on day 14 after the experience; (iii) in rats not pretreated with LFS, CVP exposure resulted in a profound increase in serum CORT concentration. In LFS pretreated rats, however, this effect was significantly reduced; (iv) three weeks after the exposure to CVP, the psychomotor response to AMPH was diminished in control rats but was normal in LFS pretreated animals. The results indicate that pretreatment with a non-chemical stressor may protect the rat against at least some of the effects of an organophosphate pesticide.

[Toxicogenomics. New perspectives for the molecular toxicology]. / Toksykogenomika. Nowe perspektywy toksykologii molekularnej.

Gene expression in the cellular genome is subject to changes caused by internal and external factors. Due to different expression of gene sets (polymorphism), cells show different morphological and functional characteristics. Environmental and occupational toxic agents may influence cells at the level of transcription and translation. The functional toxicogenomics attempts to explain those influences. Due to recent developments in molecular biology and bioinformatics, it has become possible to analyze protein transcript (toxicogenomics) and profile (toxicoproteomics). This work reports new opportunities to study gene sequencing and expression by means of the DNA chip technique (rapid analysis of the genetic polymorphism) and the microarrays technique (simultaneous analysis of hundreds or thousands of genes). The authors report examples of some practical applications of toxicogenomics in the assessment of the effects of pathological exposures to environmental and occupational toxic (carcinogenic, hepatotoxic and/or neurotoxic) agents, due to the development of new groups of biomarkers, such as biomarkers of individual susceptibility, biomarkers of toxic effects combined with the assay of the relationship between a toxic agent and its dose, and the effect measured at the level of the cellular genome and results of histopathological and biochemical tests.

[Blood plasma resistance to activated protein C as a risk factor of disseminated intravascular coagulation in acute-poisoned patients]. / Opornosc osocza na aktywne bialko C jako czynnik ryzyka rozsianego wykrzepiania sródnaczyniowego u chorych ostro zatrutych.

The aim of this work was to assess the prevalence of the blood plasma resistance to activated protein C as a risk factor of disseminated intravascular coagulation (DIC) in acute-poisoned patients. The number of examined people was 231, including 140 acute-poisoned patients (of whom 83 showed DIC's finding) and 91 clinically healthy controls. The resistance of examined plasma to the anticoagulating properties of activated protein C was assessed by Chromogenix APC-Resistance V assay (APC-R-V). Abnormal results of APC-R-V were found to be 6-fold more frequent in acute-poisoned patients with DIC syndrome: 20 of 83 (24.1%), vs 3 of 91 (3.3%) for the control. The differences were statistically significant at p=0.0001 Mean values of coefficient R were statistically significantly lower in the acute-poisoned patients with DIC syndrome than the control, p<0.001. Genetic tests preformed in 37 patients confirmed V Leiden mutation to be present people whose R index value was below 2.0. Detection of APC-R in acute-poisoned patients could facilitate implementation of suitable preventive procedure before the DIC symptoms become manifest.