Journal of Toxicological Sciences最新文献

{"title":"Establishment of an in vitro cholestasis risk assessment system using two-dimensional cultured HepaRG cells and 12 bile acids.","authors":"Toshihisa Koga,&nbsp;Kenji Takeuchi,&nbsp;Ken Umehara","doi":"10.2131/jts.48.47","DOIUrl":"https://doi.org/10.2131/jts.48.47","url":null,"abstract":"<p><p>Drug-induced liver injury (DILI) is a major cause of market withdrawal or drug-development discontinuation because of safety concerns. In this study, we focused on drug-induced cholestasis (DIC) to establish an in vitro cytotoxicity test system and analyze its sensitivity using two-dimensional (2-D) cultured HepaRG cells and 12 types of bile acids (BAs) present in the human serum. First, to detect the cytotoxicity associated with cholestasis effectively, non-toxic BA concentrations were investigated and determined to be 100-fold the human serum value (455 μM total BAs). Next, the cytotoxicity of 31 compounds that can inhibit the bile acid export pump (BSEP) and were categorized as no-DILI-concern, less-DILI-concern, and most-DILI-concern was examined. None of the no-DILI-concern compounds yielded cytotoxicity, whereas almost all less-DILI-concern compounds (with the exception of simvastatin) and most-DILI-concern compounds (with the exception of bosentan) exhibited cytotoxicity. An investigation of the cause of cytotoxicity using ³H-taurocholic acid revealed that most-DILI-concern and less-DILI-concern compounds, but not no-DILI-concern compounds, triggered the accumulation of radioactivity in the cell lysates. Thus, the onset of cytotoxicity seemed to be associated with cholestasis. The established HepaRG cytotoxicity assessment system (sensitivity of 89%, specificity of 100%, and accuracy of 97%) was mostly superior to the C_ss/BSEP IC₅₀ (> 0.1) assessment system (sensitivity of 83%, specificity of 100%, and accuracy of 72%). Therefore, the assay method using 2-D cultured HepaRG cells and 12 BAs established here can be widely applicable as a model for the in vitro potential assessment of DIC.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 1","pages":"47-56"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10489523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Melatonin therapy reverses lead exposure-induced testicular damage in rats despite the lack of effect on serum testosterone levels.","authors":"Marco A Gallegos-Reyes,&nbsp;Alejandro R Antaño-Martínez,&nbsp;Yolanda Alcaraz-Contreras,&nbsp;Jorge A Alegría-Torres,&nbsp;Juvencio Robles,&nbsp;Eunice Yáñez-Barrientos,&nbsp;Minerva Martinez-Alfaro","doi":"10.2131/jts.48.481","DOIUrl":"https://doi.org/10.2131/jts.48.481","url":null,"abstract":"<p><p>Lead (Pb) exposure induces testicular damage and infertility. The aim of this study was to analyze and compare the therapeutic effects of antioxidants or vitamin D and calcium, which have previously been shown to reduce the toxic effects of Pb co-exposure, in rats. Rats were exposed to Pb for 28 days and subsequently treated with antioxidant (melatonin, silymarin), vitamin D and calcium (VitDCa) or a combination (melatonin or silymarin with VitDCa) for 28 days. Control groups included untreated rats (no Pb exposure or therapy), rats exposed only to melatonin or silymarin and rats exposed to Pb without post exposure therapy. Pb exposure induced testicular damage, increased blood lead level (BLL) and reduced serum testosterone level (STL). Rats exposed to Pb and left untreated for 28 days showed persistent pathological testicular alterations. The two treatments that were most effective in reversing pathological testis damage and restoring spermatogenesis were melatonin and silymarin. However, silymarin and melatonin treatment resulted in significantly different serum testosterone levels in rats. Whereas melatonin therapy reduced serum testosterone to levels lower than those in control rats, silymarin increased serum testosterone to levels higher than those in controls. Our pathological analysis of testes revealed that melatonin promoted spermatogenesis and regression of Pb exposure-induced degenerative changes, despite the associated reduction in serum testosterone levels. This result suggests that circulating testosterone may not have an important role in spermatogenesis. Collectively, our results suggest that melatonin and silymarin are effective therapies against the toxic effects Pb exposure in the male reproductive system.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 8","pages":"481-486"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9935354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proteasome and p62/SQSTM1 are involved in methylmercury toxicity mitigation in mouse embryonic fibroblast cells.","authors":"Yasukazu Takanezawa,&nbsp;Ryosuke Nakamura,&nbsp;Yuka Ohshiro,&nbsp;Shimpei Uraguchi,&nbsp;Masako Kiyono","doi":"10.2131/jts.48.355","DOIUrl":"https://doi.org/10.2131/jts.48.355","url":null,"abstract":"<p><p>Methylmercury (MeHg), an environmental pollutant, disrupts and impairs cellular function. MeHg binds to various cellular proteins, causing dysfunction and misfolding, which are considered underlying causes of MeHg toxicity. The p62 protein, also termed SQSTM1, is a ubiquitin-binding protein that targets ubiquitinated substrates to undergo autophagy and plays a key role in ameliorating MeHg toxicity. p62 also delivers ubiquitinated substrates to proteasomes. However, the role of these degradation systems in mitigating MeHg toxicity remains unknown. Herein, we explored the impact of the proteasome inhibitor MG132 on MeHg toxicity and examined the toxicity of co-treatment with MG132 and MeHg in p62KO mouse embryonic fibroblasts (MEFs) by analyzing cell viability, immunoblotting, mRNA levels, immunofluorescence, and the mercury content. The proteasome inhibitor MG132 enhanced MeHg-induced cytotoxicity while reducing intracellular mercury levels in MEFs. Co-treatment with MG132 and MeHg markedly increased levels of p62 and ubiquitinated proteins. Furthermore, co-treatment with MG132 and MeHg reduced p62KO MEF viability compared to that of wild-type MEFs. Our findings suggest that the proteasome participates in mitigating MeHg cytotoxicity, while p62 may play an important role in transporting MeHg-induced ubiquitinated proteins to the proteasome, as well as in autophagy. Collectively, these results imply that p62, and proteasome, and autophagy are vital for cytoprotection against MeHg toxicity.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 6","pages":"355-361"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9618277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A case of pulmonary edema due to guanfacine intoxication with measurement of serum guanfacine concentrations.","authors":"Ryo Ayata, Motoki Fujita, Kayoko Harada, Yusuke Esaki, Yasutaka Koga, Yukari Hisamoto, Maki Asami-Noyama, Saki Takeda, Kazuki Harada, Ryosuke Tsuruta","doi":"10.2131/jts.48.641","DOIUrl":"10.2131/jts.48.641","url":null,"abstract":"<p><p>Guanfacine hydrochloride extended-release (GXR) is used to treat attention deficit hyperactivity disorder. It is a selective α2A-adrenorecepor agonist that was reported to cause QT prolongation and hypotension in the event of overdosing. We report the case of a 17-year-old man who took 226 tablets of GXR 3 mg for attempted suicide. He was found complaining of dyspnea, and emergency medical services were called. When the patient was transferred to our hospital, his Glasgow coma scale was 12 (E4V3M5). He was agitated and hypoxemic. He was intubated for invasive mechanical ventilation under sedation. His chest X-ray and computed tomography scan showed pulmonary edema. Transthoracic echocardiography showed markedly reduced cardiac function. His serum guanfacine concentration peaked on day 3 after admission. His pulmonary edema improved quickly after a decrease in serum guanfacine concentration, but cardiac decompensation persisted for about 1 month. This case reveals that the decline in cardiac function after guanfacine intoxication is prolonged even after its serum concentration has decreased.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 12","pages":"641-644"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138478094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of early-life tosufloxacin tosilate hydrate administration on growth rate, neurobehavior, and gut microbiota at adulthood in male mice.","authors":"Ayano Hasegawa,&nbsp;Takahiro Sasaki,&nbsp;Jahidul Islam,&nbsp;Takashi Tominaga,&nbsp;Tomonori Nochi,&nbsp;Kenshiro Hara,&nbsp;Kentaro Tanemura","doi":"10.2131/jts.48.149","DOIUrl":"https://doi.org/10.2131/jts.48.149","url":null,"abstract":"<p><p>Reportedly, antibiotics, which are frequently prescribed in children, have long-term effects owing to gut microbiota dysregulation. Tosufloxacin tosilate hydrate (TFLX) is the first orally administered new quinolone with high efficacy and broad-spectrum action approved as an antibacterial agent for pediatric use in Japan. However, studies on the effects of its early-stage administration are limited. Therefore, we aimed to analyze the later effects of its developmental administration by monitoring growth rate, neurobehavior, and gut microbiota in mice. The TFLX was administered via drinking water at a dose of up to 300 mg/kg for two consecutive weeks during the developmental period (4-6 weeks of age) or adulthood (8-10 weeks of age). Thereafter, the body weights of the mice were measured weekly to monitor growth rate. Behavioral tests were also conducted on 11-12-week-old mice to examine the neurobehavioral effects of the treatment. Further, to examine the effects of the treatment on microbiota, fecal samples were collected from the rectum of mice dissected at 12 weeks of age, and 16s rRNA analysis was conducted. Our results showed increased body weights after TFLX administration, without any long-term effects. Behavioral analysis suggested alterations in anxiety-like behaviors and memory recall dysregulation, and gut microbiota analysis revealed significant differences in bacterial composition. These findings indicated that TFLX administration during the developmental period affects mice growth rate, neurobehavior, and gut microbiota structure. This is the first study to report that TFLX is potentially associated with the risk of long effects.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 3","pages":"149-159"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10829220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toxicity manifestations and sex differences due to MARTA olanzapine.","authors":"Natsumi Hattori-Usami,&nbsp;Asuka Kaizaki-Mitsumoto,&nbsp;Takashi Ashino,&nbsp;Masayuki Yamamoto,&nbsp;Satoshi Numazawa","doi":"10.2131/jts.48.191","DOIUrl":"https://doi.org/10.2131/jts.48.191","url":null,"abstract":"<p><p>Olanzapine is widely used as a treatment for schizophrenia and other psychiatric disorders. Its metabolic side effects, including weight gain and hyperglycemia, are a clinical problem; however, their full mechanism is not yet clearly understood. Recently, it was reported that the accumulation of oxidative stress in the hypothalamus may cause obesity and diabetes mellitus. Epidemiologically, metabolic side effects are known to be more likely to occur in women. In the present study, we investigated and tested the hypothesis that olanzapine induces oxidative stress in the hypothalamus and induces metabolic side effects. We also examined its association with sex differences. Olanzapine was administered intraperitoneally to male and female C57BL/6 mice, and the expression levels of oxidative stress-responsible genes in the hypothalamus and cerebral cortex were measured by qRT-PCR. In addition, olanzapine was administered intraperitoneally to C57BL/6 and Nrf2 KO mice, and the expression level of total glutathione was measured. Gene expressions induced by the Keap1-Nrf2-regulated system showed different responses to olanzapine for each gene. Under the conditions of this experiment, cystine-glutamate transporter was decreased although heme oxygenase-1 and γ-glutamylcysteine synthetase were increased. It was also clear that these responses were not hypothalamus-specific. Long-term feeding with olanzapine suppressed weight gain in males but not females. No glucose intolerance was observed at 13 weeks of administration. Furthermore, deaths occurred only in females. In conclusion, this study failed to provide evidence that olanzapine induces oxidative stress in a hypothalamic-specific manner. Instead, sex differences were observed in response to long-term and high-dose olanzapine administration, suggesting that individual susceptibility to olanzapine toxicity occurred in female mice.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 4","pages":"191-202"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9294538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of MTT reducers and strongly colored substances in the Short Time Exposure test method for assessing eye irritation potential.","authors":"Takayuki Abo,&nbsp;Yuuki Deguchi,&nbsp;Takuo Yuki,&nbsp;Yutaka Takahashi,&nbsp;Masaaki Miyazawa,&nbsp;Hitoshi Sakaguchi","doi":"10.2131/jts.48.363","DOIUrl":"https://doi.org/10.2131/jts.48.363","url":null,"abstract":"<p><p>The Short Time Exposure (STE) test evaluates eye irritation potential using a 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. MTT assays may underpredict results for some substances that directly reduce MTT (i.e., MTT reducers) or interfere with absorbance because of their strong color (i.e., strongly colored substances). Based on previous research, we selected 25 substances as MTT reducers. Of these, 13 were expected to be MTT reducers at 5% dilution (5% MTT reducers) of the STE test condition. These 13 substances were then tested to determine whether the results were interfered from direct MTT reduction. Those 5% MTT reducers that were classified as irritants based on in vivo data were identified as irritants by the STE test. In addition, the low cell viability results at 5% dilution suggested that direct MTT reduction had not occurred. Next, the remaining 5% MTT reducers that were classified as non-irritants based on in vivo data were identified as non-irritants by the STE test. We then examined two strongly colored substances. One was classified as an irritant based on in vivo data and was confirmed as an irritant by the STE test. The other was classified as a non-irritant by the STE test. This was further evaluated using a medium that did not contain MTT; the result indicated that it was a non-irritant correctly. In conclusion, the STE test is useful for evaluating eye irritation potential without the drawback of underprediction for MTT reducers and strongly colored substances.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 6","pages":"363-374"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9565507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The toxicity assessment of neorudin in cynomolgus monkeys.","authors":"Yu-Bin Liu,&nbsp;Bo-Yuan Ren,&nbsp;Xing-Chen Zhou,&nbsp;Lin Zhang,&nbsp;Yun Liu,&nbsp;Can Zheng,&nbsp;Jin-Feng Wei,&nbsp;Chu-Tse Wu,&nbsp;Ji-de Jin","doi":"10.2131/jts.48.179","DOIUrl":"10.2131/jts.48.179","url":null,"abstract":"<p><p>In this study, the toxicity effects on circulatory system and respiratory system, and the acute toxicity test of recombinant neorudin (EPR-hirudin, EH) in cynomolgus monkeys were evaluated to provide reference information for clinical studies. Eighteen cynomolgus monkeys were randomly divided into three groups for single intravenous administration of 3, 30 mg/kg EH and normal saline, respectively. The changes of respiratory frequency, respiratory intensity, blood pressure and electrocardiogram before and after administration were recorded. In acute toxicity test, six cynomolgus monkeys were intravenously received EH at a single dose of 171, 257, 385, 578, 867 and 1300 mg/kg respectively. The vital signs, hematology, serum biochemistry, coagulation indexes and electrocardiogram indexes of the animals were determined before administration and on the 7th and 14th day after administration. As the results showed that there were no significant abnormal changes in respiratory frequency, respiratory intensity, blood pressure or electrocardiogram in cynomolgus monkeys after receiving EH at 3 mg/kg and 30 mg/kg, and there was no statistical difference between the treated groups and normal saline group. In the acute toxicity test, no significant abnormalities were observed in vital signs, hematology, serum biochemistry, coagulation indexes and electrocardiogram indexes of six cynomolgus monkeys at day 7 and 14 after EH administration. Furthermore, autopsies of all cynomolgus monkeys showed no abnormalities. The results of toxicokinetics showed that AUClast of the drug increased in proportion to the EH dose in the range of 171-578 mg/kg, and increased in over proportion to the EH dose in the range of 578-1300 mg/kg. The variation of Cmax was basically consistent with AUClast. In a sum, A single intravenous injection of 3 and 30 mg/kg of EH did not affect the circulatory system and respiratory system in cynomolgus monkeys and the maximum tolerated dose of EH in cynomolgus monkey is over 1300 mg/kg (equivalent to 619-1300 times of the proposed clinical equivalent dose).</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 4","pages":"179-189"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9246821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corilagin attenuates morphine-induced BV2 microglial activation and inflammation via regulating TLR2-mediated endoplasmic reticulum stress.","authors":"Sen Guan,&nbsp;Fan Miao,&nbsp;Dongmei Wang,&nbsp;Jie Hu,&nbsp;Huimiao Wang","doi":"10.2131/jts.48.387","DOIUrl":"https://doi.org/10.2131/jts.48.387","url":null,"abstract":"<p><p>Morphine-induced microglia activation and neuroinflammation have been considered as the contributors of morphine tolerance. Corilagin (Cori) has been reported to exhibit strong anti-inflammatory property. The present study aims to investigate whether and how Cori alleviates morphine-induced neuroinflammation and microglia activation. Mouse BV-2 cells were exposed to different concentrations of Cori (0.1, 1 and 10 μM) prior to morphine stimulation (200 μM). Minocycline (10 μM) acted as the positive control. Cell viability was determined by CCK-8 assay and trypan blue assay. The levels of inflammatory cytokines were determined using ELISA. IBA-1 level was examined via immunofluorescence. TLR2 expression level was examined by quantitative real-time PCR and western blot. The expression levels of corresponding proteins were measured by western blot. It was found that Cori was non-toxic to BV-2 cells but greatly inhibited morphine-induced IBA-1 expression, overproduction of pro-inflammatory cytokines, activation of NLRP3 inflammasome and endoplasmic reticulum stress (ERS), and upregulation of COX-2 and iNOS. TLR2 was negatively regulated by Cori, and could promote the activation of ERS. A high affinity between Cori and TLR2 protein was confirmed via Molecular docking investigation. Moreover, TLR2 overexpression or tunicamycin (TM), an agonist of ERS, partly abolished the inhibitory effects of Cori on morphine-induced alternations on neuroinflammation and microglial activation in BV-2 cells as above. In summary, our study suggested that Cori effectively alleviated morphine-induced neuroinflammation and microglia activation through inhibiting TLR2-mediated ERS in BV-2 cells, providing a novel potential drug to overcome morphine tolerance.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 7","pages":"387-398"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10121231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of inhalation of multi-walled carbon nanotube (MWCNT) on respiratory syncytial virus (RSV) infection in mice.","authors":"Aki Miyauchi,&nbsp;Toshi Akashi,&nbsp;Satoshi Yokota,&nbsp;Yuhji Taquahashi,&nbsp;Akihiko Hirose,&nbsp;Motoki Hojo,&nbsp;Hiroki Yoshida,&nbsp;Masahiko Kurokawa,&nbsp;Wataru Watanabe","doi":"10.2131/jts.48.411","DOIUrl":"https://doi.org/10.2131/jts.48.411","url":null,"abstract":"<p><p>Multi-walled carbon nanotubes (MWCNTs), a kind of nanomaterial, are widely used in battery electrodes and composite materials, but the adverse effects associated with their accumulation in the living body have not been sufficiently investigated. MWCNTs are a fibrous material with molecules similar to asbestos fibers, and there are concerns about its effects on the respiratory system. In this study, we conducted a risk assessment by exposing mice using a previously developed nanomaterial inhalation exposure method. We quantified the exposure in the lungs by a lung burden test, evaluated the deterioration due to pneumonia using respiratory syncytial virus (RSV) infection, and measured inflammatory cytokines in bronchoalveolar lavage fluid (BALF). As a result, in the lung burden test, the amount of MWCNT in the lung increased according to the inhalation dose. In the RSV infection experiment, CCL3, CCL5, and TGF-β, which are indicators of inflammation and lung fibrosis, were elevated in the MWCNT-exposed group. Histological examination revealed cells phagocytosing MWCNT fibers. These phagocytic cells were also seen during the recovery period from RSV infection. The present study found that MWCNT remained in the lungs for about a month or more, suggesting that the fibers may continue to exert immunological effects on the respiratory system. Furthermore, the inhalation exposure method enabled the exposure of nanomaterials to the entire lung lobe, allowing a more detailed evaluation of the effects on the respiratory system.</p>","PeriodicalId":17654,"journal":{"name":"Journal of Toxicological Sciences","volume":"48 7","pages":"411-420"},"PeriodicalIF":2.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10121236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}