Pulmonary inflammation and tumor induction in lung tumor susceptible A/J and resistant C57BL/6J mice exposed to welding fume

Background  

Welding fume has been categorized as "possibly carcinogenic" to humans. Our objectives were to characterize the lung response to carcinogenic and non-carcinogenic metal-containing welding fumes and to determine if these fumes caused increased lung tumorigenicity in A/J mice, a lung tumor susceptible strain. We exposed male A/J and C57BL/6J, a lung tumor resistant strain, by pharyngeal aspiration four times (once every 3 days) to 85 μg of gas metal arc-mild steel (GMA-MS), GMA-stainless steel (SS), or manual metal arc-SS (MMA-SS) fume, or to 25.5 μg soluble hexavalent chromium (S-Cr). Shams were exposed to saline vehicle. Bronchoalveolar lavage (BAL) was done at 2, 7, and 28 days post-exposure. For the lung tumor study, gross tumor counts and histopathological changes were assessed in A/J mice at 48 and 78 weeks post-exposure.     

Murine pulmonary responses after sub-chronic exposure to aluminum oxide-based nanowhiskers

ABSTRACT: BACKGROUND: Aluminum oxide-based nanowhiskers (AO nanowhiskers) have been used in manufacturing processes as catalyst supports, flame retardants, adsorbents, or in ceramic, metal and plastic composite materials. They are classified as high aspect ratio nanomaterials. Our aim was to assess in vivo toxicity of inhaled AO nanowhisker aerosols. METHODS: Primary dimensions of AO nanowhiskers specified by manufacturer were 2-4 nm x 2800 nm. The aluminum content found in this nanomaterial was 30% [mixed phase material containing Al(OH)3 and AlOOH]. Male mice (C57Bl/6J) were exposed to AO nanowhiskers for 4 hrs/day, 5 days/wk for 2 or 4 wks in a dynamic whole body exposure chamber. The whiskers were aerosolized with an acoustical dry aerosol generator that included a grounded metal elutriator and a venturi aspirator to enhance deagglomeration. Average concentration of aerosol in the chamber was 3.3 +/- 0.6 mg/m3 and the mobility diameter was 150 +/- 1.6 nm. Both groups of mice (2 or 4 wks exposure) were necropsied immediately after the last exposure. Aluminum content in the lung, heart, liver, and spleen was determined. Pulmonary toxicity assessment was performed by evaluation of bronchoalveolar lavage (BAL) fluid (enumeration of total and differential cells, total protein, activity of lactate dehydrogenase [LDH] and cytokines), blood (total and differential cell counts), lung histopathology and pulmonary mechanics. RESULTS: Following exposure, mean Al content of lungs was 0.25, 8.10 and 15.37 ug/g lung (dry wt) respectively for sham, 2 wk and 4 wk exposure groups. The number of total cells and macrophages in BAL fluid was 2-times higher in animals exposed for 2 wks and 6-times higher in mice exposed for 4 wks, compared to shams (p < 0.01, p < 0.001, respectively). However no neutrophilic inflammation in BAL fluid was found and neutrophils were below 1% in all groups. No significant differences were found in total protein, activity of LDH, or cytokines levels (IL-6, IFN-gamma, MIP-1alpha, TNF-alpha, and MIP-2) between shams and exposed mice. CONCLUSIONS: Sub-chronic inhalation exposures to aluminum-oxide based nanowhiskers induced increased lung macrophages, but no other inflammatory or toxic responses were observed.     

Nanosilver induces minimal lung toxicity or inflammation in a subacute murine inhalation model

Background

Multi-walled carbon nanotubes (MWCNTs) are new manufactured nanomaterials with a wide spectrum of commercial applications. To address the hypothesis that MWCNTs cause persistent pulmonary pathology, C57BL/6J mice were exposed by pharyngeal aspiration to 10, 20, 40 or 80 μg of MWCNTs (mean dimensions of 3.9 μm × 49 nm) or vehicle. Lungs were preserved at 1, 7, 28 and 56 days post- exposure to determine the potential regions and target cells for impact by MWCNT lung burden. Morphometric measurement of Sirius Red staining was used to assess the connective tissue response.

Results

At 56 days post-exposure, 68.7 ± 3.9, 7.5 ± 1.9 and 22.0 ± 5.1 percent (mean ± SE, N = 8) of the MWCNT lung burden were in alveolar macrophages, alveolar tissue and granulomatous lesions, respectively. The subpleural tissues contained 1.6% of the MWCNT lung burden. No MWCNTs were found in the airways at 7, 28 or 56 days after aspiration The connective tissue in the alveolar interstitium demonstrated a progressive increase in thickness over time in the 80 μg exposure group (0.12 ± 0.01, 0.12 ± 0.01, 0.16 ± 0.01 and 0.19 ± 0.01 μm for 1, 7, 28 and 56 days post-exposure (mean ± SE, N = 8)). Dose-response determined at 56 days post-exposure for the average thickness of connective tissue in alveolar septa was 0.11 ± 0.01, 0.14 ± .02, 0.14 ± 0.01, 0.16 ± 0.01 and 0.19 ± 0.01 μm (mean ± SE, N = 8) for vehicle, 10, 20, 40 and 80 μg dose groups, respectively.

Conclusions

The distribution of lung burden was predominately within alveolar macrophages with approximately 8% delivery to the alveolar septa, and a smaller but potentially significant burden to the subpleural tissues. Despite the relatively low fraction of the lung burden being delivered to the alveolar tissue, the average thickness of connective tissue in the alveolar septa was increased over vehicle control by 45% in the 40 μg and 73% in the 80 μg exposure groups. The results demonstrate that MWCNTs have the potential to produce a progressive, fibrotic response in the alveolar tissues of the lungs. However, the increases in connective tissue per μg dose of MWCNTs to the interstitium are significantly less than those previously found for single-walled carbon nanotubes (SWCNTs).     

重组人干扰素γ联合弓形虫STAg鼻内免疫小鼠的免疫保护作用

目的观察重组人干扰素γ(IFNγ)联合可溶性速殖子抗原(STAg)鼻内免疫小鼠诱导的黏膜和系统免疫应答及抗弓形虫感染作用。方法将BALB/c小鼠随机分为STAg组、STAg+IFNγ组和对照组,分别用20μgSTAg、20μgSTAg+1000UIFNγ和20μlPBS鼻内免疫2次,间隔14d。末次免疫后第10天,用RH株弓形虫速殖子灌胃攻击(4×104个/只),观察小鼠存活情况,并计算存活率,攻击后第43天处死全部小鼠,计数肝、脑组织内弓形虫速殖子虫荷,分离并计数肠上皮淋巴细胞(iIELs)、派伊尔氏结(PP)和脾淋巴细胞,ELISA法检测小鼠粪便弓形虫特异性sIgA和血清IgG水平。结果IFNγ联合STAg鼻内免疫能保护小鼠抵抗弓形虫攻击,小鼠存活率(93%)明显高于STAg组(60%)和对照组(47%);小鼠iIELs(1.81×105)、PP(3.21×107)和脾(3.01×107)淋巴细胞均显著增生,明显高于STAg组和对照组;粪便中sIgA水平(A492=0.435)显著高于对照组(A492=0.047),血清IgG水平(A492=0.233)显著高于STAg组(A492=0.193)和对照组(A492=0.115);肝、脑组织内弓形虫速殖子虫荷显著减少,分别比对照组减少80.90%和64.50%。结论IFNγ联合STAg鼻内免疫效果优于单独STAg免疫,IFNγ能协同STAg有效诱导黏膜和系统免疫应答,提高弓形虫攻击小鼠的存活率,降低肝、脑组织内虫荷。     

Synergistic Effect of Bolus Exposure to Zinc Oxide Nanoparticles on Bleomycin-Induced Secretion of Pro-Fibrotic Cytokines without Lasting Fibrotic Changes in Murine Lungs

Zinc oxide (ZnO) nanoparticles are widely used in various products, and the safety evaluation of this manufactured material is important. The present study investigated the inflammatory and fibrotic effects of pulmonary exposure to ZnO nanoparticles in a mouse model of pulmonary fibrosis. Pulmonary fibrosis was induced by constant subcutaneous infusion of bleomycin (BLM). Female C57BL/6Jcl mice were divided into BLM-treated and non-treated groups. In each treatment group, 0, 10, 20 or 30 µg of ZnO nanoparticles were delivered into the lungs through pharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) and the lungs were sampled at Day 10 or 14 after administration. Pulmonary exposure by a single bolus of ZnO nanoparticles resulted in severe, but transient inflammatory infiltration and thickening of the alveolar septa in the lungs, along with the increase of total and differential cell counts in BLAF. The BALF level of interleukin (IL)-1β and transforming growth factor (TGF)-β was increased at Day 10 and 14, respectively. At Day 10, the synergistic effect of BLM and ZnO exposure was detected on IL-1β and monocyte chemotactic protein (MCP)-1 in BALF. The present study demonstrated the synergistic effect of pulmonary exposure to ZnO nanoparticles and subcutaneous infusion of BLM on the secretion of pro-fibrotic cytokines in the lungs.     

Genetic Disruption of Toxoplasma gondii peroxiredoxin (TgPrx) 1 and 3 Reveals the Essential Role of TgPrx3 in Protecting Mice from Fatal Consequences of Toxoplasmosis

Toxoplasma gondii is a worldwide protozoan parasite that endangers human health and causes enormous economic losses to the animal production sector. A safe and effective vaccine or treatment is needed to reduce these hazards. In this study, we revealed the cyto-nuclear and mitochondrial localization of TgPrx1 and TgPrx3 proteins, respectively. We knocked out the T. gondii peroxiredoxin (TgPrxKO) 1 and 3 genes using a parental type II Prugniaud strain lacking KU80 and HXGPRT genes (PruΔku80Δhxgprt) via CRISPR-Cas9 technology. The successful KO was confirmed using PCR, IFAT, and Western blotting in two clones of both target genes, named TgPrx1KO and TgPrx3KO. Regarding in vitro assays, no significant variations between any of the knocked-out clones in TgPrx1KO or TgPrx3KO parasite strains, or even PruΔku80Δhxgprt, were obtained in rates of infection, proliferation, or egress. Nevertheless, mice that were infected with tachyzoites of the TgPrx3KO strain showed a marked decrease in survival rate compared with TgPrx1KO- and PruΔku80Δhxgprt-infected mice. This effect was confirmed using different mouse strains (ICR and C57BL/6J mice), sexes (male and female), and immunological backgrounds (ICR and SCID mice). In addition, TgPrx1KO and TgPrx3KO induced high levels of interferon gamma (IFN-γ) in infected mice at 8 days post infection, and increased IL-6 and IL-12p40 production from murine macrophages cultivated in vitro. The results of the present study suggested that TgPrx3 can induce anti-T. gondii immune responses that protect the mice from fatal consequences of toxoplasmosis. The results of our current and previous studies represent TgPrx3 as an excellent candidate for sub-unit vaccines, suggesting it may contribute to the control of toxoplasmosis for susceptible humans and animals.     

The splenic toxicity of water soluble multi-walled carbon nanotubes in mice

Spleen is an important immune organ and a constituting part of the reticuloendothelial system (RES). CNTs in vivo can be readily scavenged from blood and mainly entrapped by liver, spleen and lungs. Herein, water soluble multi-walled carbon nanotubes (S-MWCNTs) were used as a model to investigate the possible toxicity of carbon nanotubes (CNTs) to mouse spleen. The toxicity of various doses of S-MWCNTs was examined by carbon clearance measurement, oxidative stress assay, histopathologic and electron-microscopic examination. Compared with the control group, phagocytic activity of RES, activity of reduced glutathione, superoxide dismutase and malondialdehyde in splenic homogenate did not change significantly in 2 months. The histopathologic examination showed no observable sign of damage in spleen; however, the accumulated S-MWCNTs gradually transferred from the red pulp to the white pulp over the exposure time and might initiate the adaptive immune response of spleen.     

ESA与STAg联合滴鼻免疫小鼠诱导的特异性免疫应答

目的观察弓形虫排泄分泌抗原(ESA)与可溶性速殖子抗原(STAg)联合或单独滴鼻免疫小鼠的免疫应答效果,筛选弓形虫黏膜疫苗候选抗原。方法将40只BALB/c小鼠随机分为4组,每组10只。实验组分别用20μgSTAg、30μgESA及二抗原联合(15μgESA与10μgSTAg)滴鼻免疫2次,间隔14d,对照组用PBS以20μl/只滴鼻。于末次免疫后第14天,取血清,收集小肠冲洗液,检测特异性抗体,分离肠上皮内淋巴细胞(iIEL)和脾淋巴细胞并计数。结果整个实验期间,各组小鼠健康状况良好,体重逐渐增加。STAg组、ESA组及联合抗原组小鼠黏膜、血清中特异性抗体水平依次升高,脾淋巴细胞和iIEL增殖反应逐渐增强。联合抗原组和ESA组血清IgG抗体和小肠冲洗液sIgA升高尤为显著。同时,联合抗原组、ESA组脾淋巴细胞和iIEL增生显著高于对照组。结论ESA单独或联合STAg滴鼻免疫小鼠均能激发弓形虫特异性黏膜及系统免疫应答。两种抗原联合免疫的研究,将有助于制定更加完善的弓形虫疫苗研究策略。     

弓形虫排泄-分泌抗原鼻内免疫小鼠诱导的脾与肠相关淋巴组织细胞免疫效应及动态变化

目的观察弓形虫与Vero细胞共培养提取的排泄-分泌抗原(ESA)鼻内免疫BALB/c小鼠诱导的脾及肠相关淋巴组织(GALT)细胞免疫效应及动态变化。方法84只BALB/c小鼠随机分为实验组和对照组,实验组以ESA(20μg/只)为抗原,对照组用未接种弓形虫的细胞培养上清液(20μl/只),鼻内免疫2次,间隔2周。末次滴鼻后第1、2、3、4、5、6、7周处死小鼠,分离脾、派伊尔结(PP)及小肠上皮内淋巴细胞(IEL)并计数。结果实验组小鼠脾淋巴细胞第3周达高峰,第1、2、3周明显高于对照组;PP淋巴细胞明显增生,第3周达高峰,第1、2、3、4、5周显著高于对照组;IEL第2周增生达高峰,第1～3周显著高于对照组。结论弓形虫ESA鼻内免疫BALB/c小鼠可有效诱导不同黏膜部位及系统特异性的细胞免疫应答,且可持续较长时间。     

重组弓形虫Peroxiredoxin蛋白诱导小鼠的免疫应答及其抗弓形虫感染的保护作用

目的观察不同剂量重组弓形虫Peroxiredoxin蛋白(rTgPrx)诱导小鼠的体液免疫、细胞免疫应答及其抗弓形虫感染的保护作用。方法BALB/c小鼠60只,随机分为5组,分别用20、40、60、80μgrTgPrx(溶于100μlPBS中)和100μlPBS皮下免疫小鼠3次,间隔2周。末次免疫后第14天,用1×104个速殖子/只灌胃攻击,逐日观察小鼠健康状况。攻击后第30天,ELISA法检测小鼠血清IgG和小肠冲洗液sIgA水平,分离并计数脾淋巴细胞和小肠上皮内淋巴细胞(IEL),分离肝、脑组织内弓形虫速殖子并计数。结果60μgrTgPrx组小鼠血清IgG水平显著高于PBS、20μg和40μgrTgPrx组,小肠冲洗液sIgA组间比较差异无统计学意义;80μgrTgPrx组小鼠脾淋巴细胞数量明显高于PBS和20μgrTgPrx组,IEL数量各组间差异无统计学意义;60μg和80μgrTgPrx组小鼠脑和肝组织虫荷均低于PBS和20μgrTgPrx组。结论60μg和80μgrTgPrx皮下免疫小鼠可诱导有效的体液免疫、细胞免疫应答,且抗弓形虫感染的保护作用效果良好。     

弓形虫STAg不同接种途径免疫小鼠诱导的免疫应答

目的观察弓形虫可溶性速殖子抗原(STAg)经滴鼻、灌胃和皮下注射3种途径免疫小鼠诱导的免疫应答。方法5~6周龄BALB/c小鼠32只,随机分为4组,分别以20μgSTAg滴鼻、灌胃或皮下注射免疫小鼠2次,间隔2周,对照组不作处理。末次免疫后14d脱颈椎处死小鼠,分离脾淋巴细胞和肠上皮内淋巴细胞(IELs)并计数,ELISA法测定血清、肠冲洗液中的弓形虫特异性抗体。结果滴鼻组和皮下注射组的脾淋巴细胞数量高于灌胃组和对照组,灌胃组与对照组相近。滴鼻组的IELs数量高于皮下注射组、灌胃组和对照组,皮下注射组和灌胃组与对照组一致。皮下注射组的血清IgG水平高于滴鼻组、灌胃组和对照组,滴鼻组略高于灌胃组和对照组,但差异无显著意义。滴鼻组的小肠冲洗液sIgA水平高于皮下注射组、灌胃组和对照组,皮下注射注射组和灌胃组略高于对照组,差异无显著意义。结论20μgSTAg滴鼻免疫小鼠诱导的黏膜免疫应答优于灌胃和皮下注射;皮下注射免疫小鼠诱导的血清IgG抗体水平高于滴鼻和灌胃,但其未能诱导黏膜免疫应答。     

Single-Walled Carbon Nanotube (SWCNT)-induced interstitial fibrosis in the lungs of rats is associated with increased levels of PDGF mRNA and the formation of unique intercellular carbon structures that bridge alveolar macrophages In Situ

Background  

Nanotechnology is a rapidly advancing industry with many new products already available to the public. Therefore, it is essential to gain an understanding of the possible health risks associated with exposure to nanomaterials and to identify biomarkers of exposure. In this study, we investigated the fibrogenic potential of SWCNT synthesized by chemical vapor deposition using cobalt (Co) and molybdenum (Mo) as catalysts. Following a single oropharyngeal aspiration of SWCNT in rats, we evaluated lung histopathology, cell proliferation, and growth factor mRNAs at 1 and 21 days post-exposure. Comparisons were made to vehicle alone (saline containing a biocompatible nonionic surfactant), inert carbon black (CB) nanoparticles, or vanadium pentoxide (V₂O₅) as a known inducer of fibrosis.     

Carbon dots: a safe nanoscale substance for the immunologic system of mice

We aimed at investigating the effect of carbon dots on the BALB/c mice immune system. Mice were respectively treated with different doses of carbon dots and saline. At 1 and 9 days after intravenous administration of carbon dots, splenocyte proliferation, subpopulation of the peripheral lymphocytes, and induction of primary immune responses in mice were investigated. The results showed that high dose of carbon dots could promote the percentages of CD3+ and interferon-γ (IFN-γ) secretion and decrease the proportions of CD4+/CD8+ on the first day after administration. At 9 days post exposure, the proliferation of splenocytes had a significant increase. IFN-γ secretion and proportions of CD3+/CD19+ were also found to have an obvious promotion, and both the percentages of CD4+ and CD8+ T lymphocytes were raised, whereas the expression of cytokines made little change in the treated groups, except for IL-12 which had a slight increase in the 50-mg/kg group. The weight coefficients and histological analysis of the spleen and thymus of the treated mice exerted fewer differences compared with those from the control mice. It suggests that carbon dots could influence the immune functions of normal BALB/c mice by inducing Th1 and Tc responses and that these effects were not enough to induce the morphological change of the immune organs.     

Ipr1DNA疫苗诱导BALB/c小鼠免疫应答的探讨

目的构建真核表达质粒pBud-Ipr1-OriM,探讨其诱导BALB/c小鼠的免疫应答,为新型结核病疫苗的研制提供新思路。方法将鼠胞内病原体抗性基因1(Intracellular pathogen resistance,Ipr1)和结核分枝杆菌(Mycobacterium tubercu-losis,MTB)的复制子OriM插入真核表达质粒pBudCE4.1,构建pBud-Ipr1-OriM表达质粒(Ipr1 DNA疫苗);将BALB/c小鼠随机分为4组:生理盐水对照组、BCG组、pBud-OriM组及pBud-Ipr1-OriM组,pBud-OriM组及pBud-Ipr1-OriM组经肌肉注射免疫相应的重组质粒,BCG组经背部皮内注射BCG,每隔2周注射1次,共3次;末次免疫后2周,处死小鼠,分离血清,采用ELISA法检测小鼠血清中IL-12和IFNγ的水平;取脾组织,采用流式细胞术检测CD4+和CD8+T细胞数量,同时观察肺脾组织的病理学变化。结果经酶切、测序鉴定证实,重组真核表达质粒pBud-Ipr1-OriM(Ipr1 DNA疫苗)构建成功;pBud-Ipr1-OriM组免疫小鼠血清中IL-12水平及小鼠脾组织中CD4+和CD8+T细胞数量均高于其他组,肺脾组织未见病理学改变。结论 Ipr1 DNA疫苗能有效诱导BALB/c小鼠的细胞免疫应答,为新型结核病疫苗的研制奠定了基础。     

Small Molecule Metabolite Biomarker Candidates in Urine from Mice Exposed to Formaldehyde

Formaldehyde (FA) is a ubiquitous compound used in a wide variety of industries, and is also a major indoor pollutant emitted from building materials, furniture, etc. Because FA is rapidly metabolized and endogenous to many materials, specific biomarkers for exposure have not been identified. In this study, we identified small metabolite biomarkers in urine that might be related FA exposure. Mice were allowed to inhale FA (0, 4, 8 mg/m³) 6 h per day for 7 consecutive days, and urine samples were collected on the 7th day of exposure. Liquid chromatography coupled with time of flight-mass spectrometry and principal component analysis (PCA) was applied to determine alterations of endogenous metabolites in urine. Additionally, immune toxicity studies were conducted to ensure that any resultant toxic effects could be attributed to inhalation of FA. The results showed a significant decrease in the relative rates of T lymphocyte production in the spleen and thymus of mice exposed to FA. Additionally, decreased superoxide dismutase activity and increased reactive oxygen species levels were found in the isolated spleen cells of exposed mice. A total of 12 small molecules were found to be altered in the urine, and PCA analysis showed that urine from the control and FA exposed groups could be distinguished from each other based on the altered molecules. Hippuric acid and cinnamoylglycine were identified in urine using exact mass and fragment ions. Our results suggest that the pattern of metabolites found in urine is significantly changed following FA inhalation, and hippuric acid and cinnamoylglycine might represent potential biomarker candidates for FA exposure.     

Comparative in vivo toxicity,organ biodistribution and immune response of pristine,carboxylated and PEGylated few-layer graphene sheets in Swiss albino mice: A three month study

We present a comprehensive 3 month report on the acute and chronic toxicity of intravenously administered (20 mg kg⁻¹) few-layer graphene (FLG) and, its carboxylated (FLG-COOH) and PEGylated (FLG-PEG) derivatives in Swiss albino mice. Whole-animal in vivo tracking studies revealed that irrespective of surface modifications, graphene predominantly accumulated in lungs over a period of 24 h. Histological assessment and ex vivo confocal Raman spectral mapping revealed highest uptake and retention in lung tissue, followed by spleen, liver and kidney, with no accumulation in brain, heart or testis. FLG and FLG-COOH accumulated within organs induced significant cellular and structural damages to lungs, liver, spleen, and kidney, ranging from mild congestion to necrosis, fibrosis and glomerular filtration dysfunction, without appreciable clearance. Serum biochemistry analysis revealed that both FLG and FLG-COOH induced elevated levels of hepatic and renal injury markers. Quantitative RT-PCR studies conducted on 23 critical inflammation and immune response markers showed major alterations in gene expression profile by FLG, FLG-COOH and FLG-PEG treated animals. FLG-PEG in spite of its persistance within liver and spleen tissue for 3 months, did not induce any noticeable toxicity or organ damage, and displayed significant changes in Raman spectra, indicative of their biodegradation potential.     

Protective effect of dietary perilla oil on allergic inflammation in asthmatic mice

Perilla oil (PER) is rich in α‐linolenic acid (n‐3 fatty acid). To unravel the effects of dietary PER on allergic asthmatic inflammation, three kinds of dietary oil, including PER, corn oil (COR), and perilla compound oil (50% PER and 50% COR), were used for replacing the oil in an AIN76 feed consumed by ovalbumin (OVA)‐sensitized and challenged mice continuously for 5 wk. T‐helper type 1 lymphocyte (Th1)/T‐helper type 2 lymphocyte (Th2) and pro‐/anti‐inflammatory cytokines secreted by the cells from the airway, the lungs, and the spleen of experimental mice were determined by ELISA. The results showed that dietary PER inhibited interleukin (IL)‐1β and tumor necrosis factor (TNF)‐α secretions by lipopolysaccharide (LPS)‐stimulated lung cells, as well as interferon (IFN)‐γ and IL‐6 secretions by LPS‐stimulated splenocytes. Perilla compound oil increased the secretion ratio of IFN‐γ/IL‐5 (Th1/Th2 cytokines) in LPS‐stimulated bronchoalveolar lavage fluid cells, but decreased the ratio of IL‐6/IL‐10 (pro‐/anti‐inflammatory cytokines) in LPS‐stimulated splenocytes. The present study demonstrated that dietary PER and its compound oil protected the airways, the lungs, and the spleen from allergic inflammation in OVA‐challenged asthmatic mice, suggesting that an appropriate n‐6/n‐3 fatty acid ratio at a ratio of 1:1 or less in dietary oil may be beneficial to improve the Th2‐skewed allergic asthmatic inflammation. Practical applications: The present study demonstrated that dietary PER and its compound oil protected the airways, the lungs, and the spleen from allergic inflammation in OVA‐challenged asthmatic mice, suggesting that an appropriate n‐6/n‐3 fatty acid ratio at a ratio of 1:1 or less in dietary oil may be beneficial to improve the Th2‐skewed allergic asthmatic inflammation.     

Cytotoxicity screening of 23 engineered nanomaterials using a test matrix of ten cell lines and three different assays

Background

The most common causes of granulomatous inflammation are persistent pathogens and poorly-degradable irritating materials. A characteristic pathological reaction to intratracheal instillation, pharyngeal aspiration, or inhalation of carbon nanotubes is formation of epithelioid granulomas accompanied by interstitial fibrosis in the lungs. In the mesothelium, a similar response is induced by high aspect ratio nanomaterials, including asbestos fibers, following intraperitoneal injection. This asbestos-like behaviour of some engineered nanomaterials is a concern for their potential adverse health effects in the lungs and mesothelium. We hypothesize that high aspect ratio nanomaterials will induce epithelioid granulomas in nonadherent macrophages in 3D cultures.

Results

Carbon black particles (Printex 90) and crocidolite asbestos fibers were used as well-characterized reference materials and compared with three commercial samples of multiwalled carbon nanotubes (MWCNTs). Doses were identified in 2D and 3D cultures in order to minimize acute toxicity and to reflect realistic occupational exposures in humans and in previous inhalation studies in rodents. Under serum-free conditions, exposure of nonadherent primary murine bone marrow-derived macrophages to 0.5 μg/ml (0.38 μg/cm²) of crocidolite asbestos fibers or MWCNTs, but not carbon black, induced macrophage differentiation into epithelioid cells and formation of stable aggregates with the characteristic morphology of granulomas. Formation of multinucleated giant cells was also induced by asbestos fibers or MWCNTs in this 3D in vitro model. After 7-14 days, macrophages exposed to high aspect ratio nanomaterials co-expressed proinflammatory (M1) as well as profibrotic (M2) phenotypic markers.

Conclusions

Induction of epithelioid granulomas appears to correlate with high aspect ratio and complex 3D structure of carbon nanotubes, not with their iron content or surface area. This model offers a time- and cost-effective platform to evaluate the potential of engineered high aspect ratio nanomaterials, including carbon nanotubes, nanofibers, nanorods and metallic nanowires, to induce granulomas following inhalation.     

Evaluation of Ammonia Nitrogen Exposure in Immune Defenses Present on Spleen and Head-Kidney of Wuchang Bream (Megalobrama amblycephala)

Ammonia is one of the most important environmental factors in aquatic ecosystems. However, there are limited studies on the effects of chronic or long-term ammonia stress and its potential molecular mechanism in fish. This study aimed to investigate the immune response and molecular mechanisms in the spleen and head-kidney of fish following chronic ammonia exposure. Megalobrama amblycephala (9.98 ± 0.48 g) were exposed to different concentrations of total ammonia nitrogen (0–30 mg/L) for 30 days. Ammonia exposure caused significant increases in cortisol levels and decreases in lysozyme and complement 3/4 concentrations in the serum, indicating inhibitory effects of ammonia stress on innate immune responses. Ammonia exposure also induced concentration-dependent increases in ammonia concentrations in tissue, pathological damage and indexes of spleen and head-kidney. Additionally, the contents of immunoglobulin M (IgM), interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) as well as mRNA levels of toll-like receptors (TLRs)/Myeloid differentiation factor 88 (MyD88)-independent signaling molecules in the spleen and head-kidney were significantly downregulated after ammonia exposure. Our findings suggested that chronic ammonia exposure caused the suppression of innate and adaptive immune responses through downregulating TLR/MyD88-independent signaling. Adverse influences of chronic ammonia stress were more severe in the spleen than in the head-kidney.