Zhenlie Huang

Exposure to 1-bromopropane induces microglial changes and oxidative stress in the rat cerebellum

1-Bromopropane (1-BP), an alternative to ozone-depleting solvents, is reported to exhibit neurotoxicity and reproductive toxicity in animals and humans. However, the underlying mechanism of the toxicity remains elusive. This study was designed to identify the microglial changes and oxidative stress in the central nervous system (CNS) after 1-BP exposure. Four groups of Wistar-ST rats (n=12 each) were exposed to 0, 400, 800 and 1000ppm of 1-BP, 8h/day for 28 consecutive days. The cerebellum was dissected out in 9 rats of each group and subjected to biochemical analysis, while the brains of the remaining 3 rats were examined immunohistochemically. Exposure to 1-BP increased the levels of oxidative stress markers [thiobarbituric acid reactive substances (TBARS), protein carbonyl and reactive oxygen species (ROS)] in a dose-dependent manner. Likewise, there was also 1-BP dose-dependent increase in nitric oxide (NO) and dose-dependent decrease in protein concentrations in the cerebellum. Immunohistochemical studies showed 1-BP-induced increase in cd11b/c-positive microglia area in the white matter of the cerebellar hemispheres. The results showed that exposure to 1-BP induced morphological change in the microglia and oxidative stress, suggesting that these effects are part of the underlying neurotoxic mechanism of 1-BP in the CNS.

Occupational trichloroethylene hypersensitivity syndrome: Human herpesvirus 6 reactivation and rash phenotypes

BACKGROUND Trichloroethylene (TCE) is an industrial solvent which can cause severe generalized dermatitis, i.e., occupational TCE hypersensitivity syndrome. Reactivation of latent human herpesvirus 6 (HHV6) can occur in such patients, which has made TCE known as a causative chemical of drug-induced hypersensitivity syndrome (DIHS). OBJECTIVE This study aimed to clarify HHV6 status, cytokine profiles and their association with rash phenotypes in patients with TCE hypersensitivity syndrome. METHODS HHV6 DNA copy numbers, anti-HHV6 antibody titers, and cytokines were measured in blood prospectively sampled 5-7 times from 28 hospitalized patients with the disease. RESULTS The patients (19 had exfoliative dermatitis (ED) and 9 had non-ED type rash) generally met the diagnostic criteria for DIHS. Viral reactivation defined as increases in either HHV6 DNA (≥100 genomic copies/10(6) peripheral blood mononuclear cells) or antibody titers was identified in 24 (89%) patients. HHV6 DNA, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-5, IL-6 and IL-10 concentrations were remarkably higher in the patients than in the healthy workers (p<0.01). Positive correlations between HHV6 DNA, TNF-α, IFN-γ, IL-6 and IL-10 were significant (p<0.05) except for that between HHV6 DNA and IFN-γ. An increase in HHV6 DNA was positively associated with an increase in TNF-α on admission (p<0.01). HHV6 DNA, the antibody titers, TNF-α and IL-10 concentrations were significantly higher in ED than in the non-ED type (p<0.05). CONCLUSION Reactivated HHV6 and the increased cytokines could be biomarkers of TCE hypersensitivity syndrome. The higher-level reactivation and stronger humoral responses were associated with ED-type rash.

Upregulation of calprotectin and downregulation of retinol binding protein in the serum of workers with trichloroethylene-induced hypersensitivity dermatitis.

Upregulation of Calprotectin and Down‐regulation of Retinol Binding Protein in the Serum of Workers with Trichloroethylene‐induced Hyper‐sensitivity Dermatitis: Zhenlie HUANG, et al. Guangdong Prevention and Treatment Center for Occupational Diseases, China—

iTRAQ-based proteomic profiling of human serum reveals down-regulation of platelet basic protein and apolipoprotein B100 in patients with hematotoxicity induced by chronic occupational benzene exposure

Benzene is an important industrial chemical and an environmental contaminant, but the pathogenesis of hematotoxicity induced by chronic occupational benzene exposure (HCOBE) remains to be elucidated. To gain an insight into the molecular mechanisms and developmental biomarkers for HCOBE, isobaric tags for relative and absolute quantitation (iTRAQ) combined with two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS) were utilized. Identification and quantitation of differentially expressed proteins between HCOBE cases and healthy control were thus made. Expressions of selected proteins were confirmed by western blot and further validated by ELISA. A total of 159 unique proteins were identified (≥95% confidence), and relative expression data were obtained for 141 of these in 3 iTRAQ experiments, with fifty proteins found to be in common among 3 iTRAQ experiments. Plasminogen (PLG) was found to be significantly up-regulated, whereas platelet basic protein (PBP) and apolipoprotein B100 (APOB100) were significantly down-regulated in the serum of HCOBE cases. Additionally, the altered proteins were associated with the molecular functions of binding, catalytic activity, enzyme regulator activity and transporter activity, and involved in biological processes of apoptosis, developmental and immune system process, as well as response to stimulus. Furthermore, differential expressions of PLG, PBP and APOB100 were confirmed by western blot, and the clinical relevance of PBP and APOB100 with HCOBE was validated by ELISA. Overall, our results showed that lowered expression of PBP and APOB100 proteins served as potential biomarkers of HCOBE, and may play roles in the benzene-induced immunosuppressive effects and disorders in lipid metabolism.

Proteomic analysis of hippocampal proteins of F344 rats exposed to 1-bromopropane

1-Bromopropane (1-BP) is a compound used as an alternative to ozone-depleting solvents and is neurotoxic both in experimental animals and human. However, the molecular mechanisms of the neurotoxic effects of 1-BP are not well known. To identify the molecular mechanisms of 1-BP-induced neurotoxicity, we analyzed quantitatively changes in protein expression in the hippocampus of rats exposed to 1-BP. Male F344 rats were exposed to 1-BP at 0, 400, or 1000 ppm for 8h/day for 1 or 4 weeks by inhalation. Two-dimensional difference in gel electrophoresis (2D-DIGE) combined with matrix-assisted laser-desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) were conducted to detect and identify protein modification. Changes in selected proteins were further confirmed by western blot. 2D-DIGE identified 26 proteins with consistently altered model (increase or decrease after both 1- and 4-week 1-BP exposures) and significant changes in their levels (p<0.05; fold change ≥ ± 1.2) at least at one exposure level or more compared with the corresponding controls. Of these proteins, 19 were identified by MALDI-TOF-TOF/MS. Linear regression analysis of 1-BP exposure level identified 8 differentially expressed proteins altered in a dose-dependent manner both in 1- and 4-week exposure experiments. The identified proteins could be categorized into diverse functional classes such as nucleocytoplasmic transport, immunity and defense, energy metabolism, ubiquitination-proteasome pathway, neurotransmitter and purine metabolism. Overall, the results suggest that 1-BP-induced hippocampal damage involves oxidative stress, loss of ATP production, neurotransmitter dysfunction and inhibition of ubiquitination-proteasome system.

Proteomic identification of carbonylated proteins in F344 rat hippocampus after 1-bromopropane exposure

1-Bromopropane (1-BP) is neurotoxic in both experimental animals and humans. Previous proteomic analysis of rat hippocampus implicated alteration of protein expression in oxidative stress, suggesting that oxidative stress plays a role in 1-BP-induced neurotoxicity. To understand this role at the protein level, we exposed male F344 rats to 1-BP at 0, 400, or 1000 ppm for 8h/day for 1 week or 4 weeks by inhalation and quantitated changes in hippocampal protein carbonyl using a protein carbonyl assay, two-dimensional gel electrophoresis (2-DE), immunoblotting, and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-TOF/MS). Hippocampal reactive oxygen species and protein carbonyl were significantly increased, demonstrating 1-BP-associated induction of oxidative stress and protein damage. MALDI-TOF-TOF/MS identified 10 individual proteins with increased carbonyl modification (p < 0.05; fold-change ≥ 1.5). The identified proteins were involved in diverse biological processes including glycolysis, ATP production, tyrosine catabolism, GTP binding, guanine degradation, and neuronal metabolism of dopamine. Hippocampal triosephosphate isomerase (TPI) activity was significantly reduced and negatively correlated with TPI carbonylation (p < 0.001; r = 0.83). Advanced glycation end-product (AGE) levels were significantly elevated both in the hippocampus and plasma, and hippocampal AGEs correlated negatively with TPI activity (p < 0.001; r = 0.71). In conclusion, 1-BP-induced neurotoxicity in the rat hippocampus seems to involve oxidative damage of cellular proteins, decreased TPI activity, and elevated AGEs.

Effects of exposure to 1-bromopropane on astrocytes and oligodendrocytes in rat brain.

Effects of Exposure to 1‐Bromopropane on Astrocytes and Oligodendrocytes in Rat Brain: Sahabudeen Sheik MOHIDEEN, et al. Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya University—

Hippocampal phosphoproteomics of F344 rats exposed to 1-bromopropane.

1-Bromopropane (1-BP) is neurotoxic in both experimental animals and human. To identify phosphorylated modification on the unrecognized post-translational modifications of proteins and investigate their role in 1-BP-induced neurotoxicity, changes in hippocampal phosphoprotein expression levels were analyzed quantitatively in male F344 rats exposed to 1-BP inhalation at 0, 400, or 1000 ppm for 8 h/day for 1 or 4 weeks. Hippocampal protein extracts were analyzed qualitatively and quantitatively by Pro-Q Diamond gel staining and SYPRO Ruby staining coupled with two-dimensional difference in gel electrophoresis (2D-DIGE), respectively, as well as by matrix-assisted laser-desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) to identify phosphoproteins. Changes in selected proteins were further confirmed by Manganese II (Mn(2+))-Phos-tag SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Bax and cytochrome c protein levels were determined by western blotting. Pro-Q Diamond gel staining combined with 2D-DIGE identified 26 phosphoprotein spots (p<0.05), and MALDI-TOF/MS identified 18 up-regulated proteins and 8 down-regulated proteins. These proteins are involved in the biological process of response to stimuli, metabolic processes, and apoptosis signaling. Changes in the expression of phosphorylated 14-3-3 θ were further confirmed by Mn(2+)-Phos-tag SDS-PAGE. Western blotting showed overexpression of Bax protein in the mitochondria with down-regulation in the cytoplasm, whereas cytochrome c expression was high in the cytoplasm but low in the mitochondria after 1-BP exposure. Our results suggest that the pathogenesis of 1-BP-induced hippocampal damage involves inhibition of antiapoptosis process. Phosphoproteins identified in this study can potentially serve as biomarkers for 1-BP-induced neurotoxicity.

Serum plasminogen as a potential biomarker for the effects of low-dose benzene exposure

Exposure to low-dose benzene may lead to hematotoxicity and cause health problems. Though peripheral blood cell count is widely used in benzene exposure assessment and health risk assessment, the reports regarding the effects of low-dose benzene exposure on blood cell count remain inconsistent. To uncover more sensitive biomarkers for low-dose benzene exposure, our previous study screened out three potential serum proteins-plasminogen (PLG), platelet basic protein (PBP) and apolipoprotein B100 (ApoB100)-as biomarkers from chronic benzene poisoning patients by using proteomic analysis. In the present study, we verify the three serum proteins as biomarkers for the effects of low-dose benzene exposure in a large low-dose benzene exposure population. The study showed that serum PLG increased in benzene exposed workers and was positively correlated with benzene exposure levels. However, no significant changes in serum PBP or ApoB100 were found in the benzene exposed workers. To explore whether the candidate serum proteins are associated with hematotoxicity, the study population was regrouped into two groups, based on their WBC counts. Our results showed that the workers with high serum PLG levels suffered higher risk of WBC abnormalities than did workers with low serum PLG levels. Taken together, these findings indicate that the increase in serum PLG might be associated with low-dose benzene exposure and benzene-induced hematotoxicity. Thus, we suggest serum PLG could be used as a potential biomarker for the effects of low-dose benzene exposure.

Pulmonary hypofunction due to calcium carbonate nanomaterial exposure in occupational workers: a cross-sectional study

Abstract Calcium carbonate nanomaterials (nano-CaCO3) are widely used in both manufacturing and consumer products, but their potential health hazards remain unclear. The objective of this study was to survey workplace exposure levels and health effects of workers exposed to nano-CaCO3. Personal and area sampling, as well as real-time and dust monitoring, were performed to characterize mass exposure, particle size distribution, and particle number exposure. A total of 56 workers (28 exposed workers and 28 unexposed controls) were studied in a cross-sectional study. They completed physical examinations, spirometry, and digital radiography. The results showed that the gravimetric nano-CaCO3 concentration was 5.264 ± 6.987 mg/m3 (0.037–22.192 mg/m3) at the workplace, and 3.577 ± 2.065 mg/m3 (2.042–8.161 mg/m3) in the breathing zone of the exposed workers. The particle number concentrations ranged from 8193 to 39 621 particles/cm3 with a size range of 30–150 nm. The process of packing had the highest gravimetric and particle number concentrations. The particle number concentration positively correlated with gravimetric concentrations of nano-CaCO3. The levels of hemoglobin, creatine phosphokinase (CK), lactate dehydrogenase, and high-density lipoprotein cholesterol (HDL-C) in the nano-CaCO3 exposure group increased significantly, but the white blood cell count (WBC), Complement 3 (C3), total protein (TP), uric acid, and creatinine (CREA) all decreased significantly. The prevalence rate of pulmonary hypofunction was significantly higher (p = 0.037), and the levels of vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, peak expiratory flow and forced expiratory flow 25% (FEF 25%), FEF 25–75% were negatively correlated with gravimetric concentrations of nano-CaCO3 (p < 0.05). Logistic analysis showed that nano-CaCO3 exposure level was associated with pulmonary hypofunction (p = 0.005). Meanwhile, a dose-effect relationship was found between the accumulated gravimetric concentrations of nano-CaCO3 and the prevalence rate of pulmonary hypofunction (p = 0.048). In conclusion, long-term and high-level nano-CaCO3 exposure can induce pulmonary hypofunction in workers. Thus, lung function examination is suggested for occupational populations with nano-CaCO3 exposure. Furthermore, future health protection efforts should focus on senior workers with accumulation effects of nano-CaCO3 exposure.