1.In vitro cultured calculus bovis alleviates cerebral ischemia/reperfusion injury through regulating microglial polarization and inhibiting NLRP3.
Tanlu CHU ; Wei ZHANG ; Jingwen CHEN ; Zeyue PAN ; Lingfeng WANG ; Xiaoming ZHONG ; Fengmei QIU ; Zhen HUANG
Journal of Zhejiang University. Medical sciences 2025;54(3):360-371
OBJECTIVES:
To investigate the effect of in vitro cultured calculus bovis (ICCB) on cerebral ischemia/reperfusion injury (CIRI) and its mechanism.
METHODS:
A CIRI rat model and a cell model were induced by middle cerebral artery occlusion (MCAO) in Sprague Dawley rats and oxygen glucose deprivation/reperfusion (OGD/R) in BV2 cells, respectively. The CIRI rat model was evaluated using the modified neurological severity score (mNSS), brain water content, and cerebral infarction volume after 1.5 h of ischemia followed by 72 h of reperfusion. Histopathological changes in the cortex and hippocampal CA1 region were observed with hematoxylin and eosin staining. Microglial polarization and NOD-like receptor thermal protein domain associated protein (NLRP) 3 inflammasome expression in the cortex were examined by immunofluorescence. BV2 cell viability was measured via MTT assay after treatment with ICCB and Nigericin. The expressions of NLRP3, ASC, caspase-1 proteins and inflammatory cytokines were detected with Western blotting in OGD/R treated BV2 cells (0.5 h OGD+24 h reperfusion) and in cells pretreated with Nigericin for 24 h.
RESULTS:
ICCB treatment significantly improved neurological function, reduced cerebral infarct volume and brain water content, and mitigated pathological damage in the cortical and hippocampal CA1 regions of rats subjected to CIRI (all P<0.05). ICCB promoted the transition of cortical microglia from M1 to M2 phenotypes and suppressed NLRP3 activation in microglial cells (all P<0.01). ICCB significantly down-regulated the expression of NLRP3, ASC, and caspase-1 proteins, and reduced the secretion of IL-18 and IL-1β in BV2 cells of OGD/R model (all P<0.01). In addition, Nigericin significantly reversed the salvage effect of ICCB on model cells (both P<0.01) and the modulation of inflammatory cytokines (P<0.05).
CONCLUSIONS
ICCB exerts a protective effect against CIRI by mitigating neuroinflammation, through the reduction of M1 microglial polarization, promotion of M2 conversion, and suppression of the NLRP3/ASC/caspase-1 signaling pathway.
Animals
;
Rats, Sprague-Dawley
;
Reperfusion Injury/prevention & control*
;
Microglia/metabolism*
;
Rats
;
NLR Family, Pyrin Domain-Containing 3 Protein
;
Brain Ischemia/metabolism*
;
Male
2.Scleromitrion diffusum reverses epithelial-mesenchymal transi-tion of gastric mucosa in rats with gastric precancerous lesions.
Luping MA ; Xin ZUO ; Weikai ZHU ; Jiyan LI ; Yanyan ZHAO ; Jingyuan ZHANG ; Hui SHEN
Journal of Zhejiang University. Medical sciences 2025;54(3):342-349
OBJECTIVES:
To investigate the effect of Scleromitrion diffusum on gastric mucosal epithelial-mesenchymal transition (EMT) in rats with gastric precancerous lesion.
METHODS:
Fifty SD rats were randomly divided into blank control group (n=11), model control group (n=13), Scleromitrion diffusum (SD) group (n=13) and vitase group (n=13). Gastric precancerous lesion animal model was prepared by 1-methyl-3-nitro-1-nitrosoguanidine complex polyfactor method, and the drugs were administrated by gavage once a day for 6 weeks. The pathological changes of gastric mucosa were observed with hematoxylin and eosin staining, the expression of EMT marker proteins were detected with immunohistochemical staining and Western blotting.
RESULTS:
Compared with the model control group, the gastric mucosal injury was significantly attenuated in the Scleromitrion diffusum group, the mucosal tissue structure gradually recovered, the saccular expansion area was reduced, and the inflammatory infiltration was ameliorated. The expression of epithelial cadherin was higher, and the expression of neural cadherin and vimentin in the Scleromitrion diffusum group were lower than those of model control group (all P<0.05).
CONCLUSIONS
Scleromitrion diffusum can ameliorate gastric mucosal injury in rats with gastric precancerous lesion by reversing the EMT.
Animals
;
Rats
;
Rats, Sprague-Dawley
;
Epithelial-Mesenchymal Transition/drug effects*
;
Precancerous Conditions/metabolism*
;
Gastric Mucosa/metabolism*
;
Stomach Neoplasms/drug therapy*
;
Male
;
Cadherins/metabolism*
3.Shenge powder inhibits myocardial fibrosis in rats with post-myocardial infarction heart failure through LOXL2/TGF-β1/IL-11 signaling pathway.
Hang XIE ; Boyong QIU ; Haitao LI ; Ruoyu SHI
Journal of Zhejiang University. Medical sciences 2025;54(3):350-359
OBJECTIVES:
To investigate the effect of Shenge powder (SGP) on myocardial fibrosis in rats with heart failure after myocardial infarction and its relation with lysyl oxidase like protein 2 (LOXL2)/transforming growth factor-β1 (TGF-β1)/IL-11 signaling pathway.
METHODS:
Seventy-two SPF male SD rats were divided into blank control group, model control group, SGP small dose group, SGP large dose group, positive control group, SGP large dose+LOXL2 activator group, with 12 rats in each group. Except for the blank control group, post-myocardial infarction heart failure was induced by coronary constriction. Corresponding treatments were given immediately after successful modeling, once a day for 4 weeks. Left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) in rats were detected by color Doppler ultrasound imaging. Levels of IL-1β and IL-6 in serum were analyzed by ELISA method. Myocardial collagen volume fraction (CVF) was evaluated by Masson staining. Expressions of collagen Ⅰ and α-smooth muscle actin (α-SMA) in myocardial tissue were detected by immunohistochemical staining. The mRNA expressions of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in myocardial tissue were detected by qRT-PCR. Expression of LOXL2, TGF-β1, and IL-11 proteins in myocardial tissue were detected by Western blotting.
RESULTS:
Compared with the blank control group, the LVFS and LVEF of the model control group decreased, the levels of serum IL-6 and IL-1β elevated, and the CVF value, the expressions of collagen Ⅰ and α-SMA in myocardial tissue, MMP-9 and TIMP-1 mRNA, and LOXL2, TGF-β1, IL-11 proteins increased (all P<0.05). Compared with the model control group, the LVFS and LVEF of SGP small dose group, SGP large dose group and positive control group increased, the levels of serum IL-6 and IL-1β decreased, and the CVF value, the expressions of collagen Ⅰ and α-SMA in myocardial tissue, MMP-9 and TIMP-1 mRNA, and LOXL2, TGF-β1, IL-11 proteins decreased (all P<0.05); while LOXL2 activator reversed the improvement effect of high-dose SGP on myocardial fibrosis in heart failure rats after myocardial infarction.
CONCLUSIONS
Shenge powder may inhibit myocardial fibrosis in heart failure rats after myocardial infarction by inhibiting the LOXL2/TGF-β1/IL-11 pathway.
Animals
;
Male
;
Rats, Sprague-Dawley
;
Myocardial Infarction/complications*
;
Transforming Growth Factor beta1/metabolism*
;
Signal Transduction/drug effects*
;
Drugs, Chinese Herbal/therapeutic use*
;
Rats
;
Heart Failure/pathology*
;
Myocardium/metabolism*
;
Fibrosis
;
Amino Acid Oxidoreductases/metabolism*
;
Interleukin-11/metabolism*
;
Tissue Inhibitor of Metalloproteinase-1/metabolism*
;
Matrix Metalloproteinase 9/metabolism*
4.Study on the targets and mechanisms of 7-hydroxyethyl chrysin in prevention and treatment of high-altitude cerebral edema using proteomics technology.
Dongmei ZHANG ; Xiaolin LI ; Chenyu YANG ; Linlin JING ; Lei HE ; Huiping MA
Journal of Zhejiang University. Medical sciences 2025;54(4):549-558
OBJECTIVES:
To investigate the targets and mechanisms of 7-hydroxyethyl chrysin (7-HEC) in prevention and treatment of high-altitude cerebral edema (HACE) in rats.
METHODS:
Fifty-four male Wistar rats were randomly divided into normal control group, HACE model group, and 7-HEC-treated group (18 rats in each group). Except for the normal control group, rats in the two other groups were exposed to a hypobaric hypoxic chamber simulating a 7000 m altitude for 72 h to establish the HACE model. The 7-HEC-treated group was intraperitoneally injected with 7-HEC (150 mg·kg-¹·d-¹) for 3 consecutive days before modeling, while the model group received equivalent isotonic sodium chloride solution. Tandem Mass Tag (TMT) proteomics technology was used to detect differentially expressed proteins (DEPs) with screening criteria set at a fold change >1.2 and P<0.05. Western blotting was used to verify the expression levels of target proteins. Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) network analysis were performed.
RESULTS:
Compared with the normal control group, 256 DEPs were identified in the HACE model group. Compared with the HACE model group, 87 DEPs were identified in the 7-HEC-treated group. Among them, 19 DEPs that were dysregulated in the HACE model group were restored after 7-HEC intervention, of which seven (HSPA4, Arhgap20, SERT, HACL1, CCDC43, POLR3A, and PCBD1) were confirmed by Western blotting. GO enrichment analysis of the DEPs between the HACE model and 7-HEC-treated groups revealed their involvement in 13 biological processes, five cellular components, and two molecular functions. KEGG pathway analysis indicated associations with the mRNA surveillance pathway, Th17 cell differentiation, serotonergic synapse, RNA polymerase, protein processing in the endoplasmic reticulum, peroxisome, neuroactive ligand-receptor interaction, folate biosynthesis. PPI network analysis demonstrated that HSPA4, POLR3A, and HACL1, which were validated by Western blotting, interacted with multiple signaling pathways and ranked among the top 20 hub proteins by degree value, suggesting their potential role as core regulatory factors. Arhgap20, SERT and PCBD1 also exhibited interactions with several proteins, suggesting their potential as key regulatory proteins, whereas no interactions for CCDC43 were identified.
CONCLUSIONS
This study applied TMT proteomics to identify seven potential therapeutic targets of 7-HEC for the prevention and treatment of HACE. These targets may be involved in the pathogenesis of HACE through multiple pathways, including maintaining cellular homeostasis, ameliorating oxidative stress, regulating energy metabolism, and reducing vascular permeability.
Animals
;
Male
;
Proteomics/methods*
;
Rats, Wistar
;
Flavonoids/therapeutic use*
;
Rats
;
Brain Edema/etiology*
;
Altitude Sickness/metabolism*
;
Protein Interaction Maps
5.Protective Effects of Low-Dose Irradiated Autologous Peripheral Blood Reinfusion on Radiation -Induced Leukopenia in Rats: An Experimental Study.
Gao-Feng HE ; Shuang GE ; Li-Ping SUN ; De-Qing WANG ; Yang YU
Journal of Experimental Hematology 2025;33(2):511-519
OBJECTIVE:
To investigate the effects of low-dose irradiated autologous peripheral blood reinfusion (LDIAPBR) on a rat model of radiation-induced leukopenia.
METHODS:
The rats were randomly divided into four groups. In the LDIAPBR group, LDIAPBR was performed 1 day before modeling (10% of the total circulating blood volume was withdrawn, irradiated with 100 mGy ex vivo, and completely reinfused). Meanwhile, the normal group and model group only underwent blood withdrawal and reinfusion of the same proportion without blood irradiation. Except for the normal group, all groups were subjected to 1 Gy X-ray whole-body irradiation to establish a radiation-induced leukopenia rat model. The positive drug group received subcutaneous injection of rhG-CSF after modeling. It was monitored that the general condition of the rats, peripheral blood cell counts, immune organ indices, bone marrow nucleated cell counts and viability, and the pathological analysis of bone marrow sections was conducted.
RESULTS:
The LDIAPBR group exhibited significant improvements in overall condition compared to the model group. Notably, compared with the model group, peripheral blood leukocyte and lymphocyte counts were markedly higher in the LDIAPBR group. Furthermore, there was a significant increase in both the number and viability of nucleated cells in the bone marrow. Pathological examination of bone marrow sections revealed increased nucleated cell density and reduced cavity area in the LDIAPBR group.
CONCLUSION
LDIAPBR can effectively improve hematological parameters and bone marrow hematopoietic function in a rat model of radiation-induced leukopenia, providing a new approach for the prevention and treatment of radiation-related injuries.
Animals
;
Leukopenia/prevention & control*
;
Rats
;
Blood Transfusion, Autologous
;
Whole-Body Irradiation
;
Radiation Injuries, Experimental/therapy*
6.Mechanism of Regulating MK2 to Improve Bone Marrow Inflammatory Damage after Hematopoietic Stem Cell Transplantation.
Zhao-Hui WANG ; Bo LONG ; Yu-Han WANG ; Zhi-Ting LIU ; Zi-Jie XU ; Shuang DING
Journal of Experimental Hematology 2025;33(5):1453-1460
OBJECTIVE:
To investigate the role of MK2 inhibitor MMI-0100 on inflammatory response after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and related mechanisms.
METHODS:
An allo-HSCT mouse model was established. Recipient rats were randomly divided into BMT+NaCl group and BMT+MMI-0100 group, and were injected with NaCl and MMI-0100 every day after transplantation, respectively. Samples of the two groups were collected on d 7 and 14, femur paraffin sections were stained with HE, and pathological changes in the bone marrow cavity were observed under the light microscope. The gene and protein expression levels of pro-inflammatory cytokines IL-1β and IL-18 were detected by qPCR and Western blot. Macrophage typing was detected by flow cytometry. The expression levels of NLRP3 and Caspase-1 were detected by Western blot.
RESULTS:
Inflammatory cell infiltration in the bone marrow cavity was significantly reduced in the BMT+MMI-0100 group. Western blot results showed that the protein expression levels of IL-1β and IL-18 in the BMT+MMI-0100 group were decreased compared to the BMT+NaCl group on day 7 and day 14 (all P <0.01). The qPCR results showed that compared to the BMT+NaCl group, the IL-18 gene expression levels in the BMT+MMI-0100 group were significantly reduced on day 7 and day 14 (both P <0.01). In the BMT+MMI-0100 group, the expression level of IL-1β gene decreased on day 7 (P <0.05), but increased and was higher than that in the BMT+NaCl group on day 14 (P <0.05). Flow cytometry results showed that the expression of M1 macrophages and M1/M2 ratio decreased in the BMT+MMI-0100 group compared to BMT+NaCl group (all P <0.05). Western blot results showed that the protein expression levels of NLRP3 and Caspase-1 in the BMT+MMI-0100 group were lower than those in the BMT+NaCl group (all P <0.05).
CONCLUSION
MMI-0100 can ameliorate bone marrow inflammatory injury after allo-HSCT and may act by reducing NLRP3 expression to promote M2 polarization.
Animals
;
Interleukin-1beta/metabolism*
;
Rats
;
Interleukin-18/metabolism*
;
Hematopoietic Stem Cell Transplantation/adverse effects*
;
Mice
;
NLR Family, Pyrin Domain-Containing 3 Protein/metabolism*
;
Inflammation
;
Bone Marrow/pathology*
;
Protein Serine-Threonine Kinases/metabolism*
;
Intracellular Signaling Peptides and Proteins/antagonists & inhibitors*
;
Caspase 1/metabolism*
;
Macrophages
;
Transplantation, Homologous
7.Association of angiotensin Ⅱ type 1 receptor autoantibody and sperm motility in human semen.
Dao-Qin TU ; Yu-Huan YANG ; Gui-Fang YANG ; Yi-Nan ZHANG ; Yao CHEN ; Xue-Ming LI ; Yu-Hui SHI ; Xiao-Li YANG ; Feng WANG
National Journal of Andrology 2025;31(5):387-394
OBJECTIVE:
To investigate the relationship between angiotensin Ⅱ type 1 receptor autoantibody (AT1-AA) and semen parameters. Methods: The semen samples of 820 male patients who were treated in the Reproductive Medicine Center of Taiyuan Central Hospital from August 2022 to August 2023 were retrospectively analyzed. The levels of AT1-AA and Ang Ⅱ of semen were detected by ELISA, and the function of AT1-AA was detected by cardiomyocyte beating assay in suckling rats. The patients were divided into low group, median group and high group according to the OD values of AT1-AA. The differences in general data and semen parameters between different groups were analyzed. And the correlation between AT1-AA level and semen parameters in semen of all study subjects was analyzed by the method of Spearman analysis. And the relationships between AT1-AA OD value, Ang Ⅱ level and semen parameters in the AT1-AA high value group were analyzed as well.
RESULTS:
AT1-AA was present in semen with good function. There was no significant difference in the general data of patients in different AT1-AA levels (P>0.05). In the comparison of semen parameters among the groups with different levels of AT1-AA, there were differences in sperm concentration, PR concentration, NP%, and ALH among the three groups (P<0.05). And AT1-AA OD value was positively correlated with total sperm count, sperm concentration, PR concentration, and NP%, and negatively correlated with semen volume (P<0.05). In the AT1-AA high value group, the OD value of AT1-AA in semen was negatively correlated with inactive sperm, and positively correlated with total motility ([PR+NP]%), curve rate, mean path rate, and ALH. However, there was no correlation between the level of Ang Ⅱ in semen and semen parameters (P>0.05).
CONCLUSION
The presence of AT1-AA in semen may be associated with the promotion of sperm motility.
Male
;
Humans
;
Autoantibodies
;
Sperm Motility
;
Semen
;
Retrospective Studies
;
Receptor, Angiotensin, Type 1/immunology*
;
Animals
;
Rats
;
Angiotensin II
;
Adult
;
Sperm Count
;
Semen Analysis
;
Receptor, Angiotensin, Type 2/immunology*
8.Single exposure to near-threshold 5G millimeter wave modifies restraint stress responses in rats.
Akiko MATSUMOTO ; Ikumi ENDO ; Etsuko IJIMA ; Akimasa HIRATA ; Sachiko KODERA ; Masayoshi ICHIBA ; Mikiko TOKIYA ; Takashi HIKAGE ; Hiroshi MASUDA
Environmental Health and Preventive Medicine 2025;30():33-33
BACKGROUND:
In response to growing concerns about the health effects of quasi-millimeter waves (qMMW) used in 5th-generation wireless systems, conservative whole-body exposure thresholds based on indirect evidence have been proposed. The guidelines define a whole-body average specific absorption rate (WBA-SAR) of 4 W/kg which causes a 1 °C increase in core temperature, as the operational threshold for adverse health effects. To address the lack of direct evidence, we recently reported that a 30-minute exposure to qMMW at 4.6 W/kg resulted in a 1 °C increase in rat core temperature. Here, we further analyzed the near-threshold stress response for the first time, using biological samples from the aforementioned and additional experiments.
METHODS:
A total of 59 young Sprague-Dawley rats (240-322 g) were exposed to 28 GHz for 40 minutes at WBA-SARs of 0, 3.7, and 7.2 W/kg, under normal (22.5 °C, 45-55% humidity), and heat (32 °C, 70% humidity) conditions. Rats were restrained in acrylic holders for dose control. We repeatedly measured serum and urinary biomarkers of stress response, aggregated the data, and analyzed them using a single statistical mixed model to subtract the effects of sham exposure and between-subject variation.
RESULTS:
Sham exposure induced stress responses, suggesting an effect of restraint. After the subtraction of the sham exposure effect, 28 GHz appeared to induce stress responses as evidenced by elevated serum-free corticosterone 1 or 3 days after the exposure, which was more evident in animals with a change in rectal temperature exceeding 1 °C. Urinary-free catecholamines demonstrated an inhibitory property of 28 GHz frequency exposure on the stress response as evidenced by noradrenaline on the day of exposure. Heat exposure enhanced this effect, suggesting a possible role of noradrenaline in heat dissipation by promoting cutaneous blood flow, a notion supported by the correlation between noradrenaline levels and tail surface temperature, a critical organ for heat dissipation.
CONCLUSIONS
This study is the first to demonstrate that qMMW whole-body exposure can alter the stress response as indicated by corticosterone and noradrenaline at near-threshold levels. Our findings may provide insight into the biological basis of the whole-body exposure thresholds in the international guidelines.
Animals
;
Rats
;
Rats, Sprague-Dawley
;
Male
;
Restraint, Physical
;
Stress, Physiological/radiation effects*
;
Corticosterone/blood*
;
Biomarkers/blood*
;
Microwaves/adverse effects*
9.Peripheral blood mitochondrial DNA copy number as a predictor of steatotic liver disease development: insights from epidemiological and experimental studies.
Genki MIZUNO ; Atsushi TESHIGAWARA ; Hiroya YAMADA ; Eiji MUNETSUNA ; Yoshiki TSUBOI ; Yuji HATTORI ; Mirai YAMAZAKI ; Yoshitaka ANDO ; Itsuki KAGEYAMA ; Takuya WAKASUGI ; Naohiro ICHINO ; Keisuke OSAKABE ; Keiko SUGIMOTO ; Ryosuke FUJII ; Hiroaki ISHIKAWA ; Nobutaka OHGAMI ; Koji OHASHI ; Koji SUZUKI
Environmental Health and Preventive Medicine 2025;30():42-42
BACKGROUND:
Mitochondria, which harbor their own genome (mtDNA), have attracted attention due to the potential of mtDNA copy number (mtDNA-CN) as an indicator of mitochondrial dysfunction. Although mtDNA-CN has been proposed as a simple and accessible biomarker for metabolic disorders such as metabolic dysfunction-associated steatotic liver disease, the underlying mechanisms and the causal relationship remain insufficiently elucidated. In this investigation, we combined longitudinal epidemiological data, animal studies, and in vitro assays to elucidate the potential causal relationship between reduced mtDNA-CN and the development of steatotic liver disease (SLD).
METHODS:
We conducted a longitudinal study using data from a health examination cohort initiated in 1981 in Yakumo, Hokkaido, Japan. Data from examinations performed in 2015 and 2022 were analyzed, focusing on 76 subjects without SLD at baseline (2015) to assess the association between baseline mtDNA-CN and subsequent risk of SLD development. In addition, 28-day-old SD rats were fed ad libitum on a 45% high-fat diet and dissected at 2 and 8 weeks of age. Blood and liver mtDNA-CN were measured and compared at each feeding period. Additionally, in vitro experiments were performed using HepG2 cells treated with mitochondrial function inhibitors to induce mtDNA-CN depletion and to examine its impact on intracellular lipid accumulation.
RESULTS:
Epidemiological analysis showed that the subjects with low mtDNA-CN had a significantly higher odds ratio for developing SLD compared to high (odds ratio [95% confidence interval]: 4.93 [1.08-22.50]). Analysis of the animal model showed that 8 weeks of high-fat diet led to the development of fatty liver and a significant decrease in mtDNA-CN. A further 2 weeks of high-fat diet consumption resulted in a significant decrease in hepatic mtDNA-CN, despite the absence of fatty liver development, and a similar trend was observed for blood. Complementary in vitro experiments revealed that pharmacologically induced mitochondrial dysfunction led to a significant reduction in mtDNA-CN and was associated with increases in intracellular lipid accumulation in HepG2 cells.
CONCLUSIONS
Our findings suggest that reduced mtDNA-CN may contribute causally to SLD development and could serve as a convenient, noninvasive biomarker for early detection and risk assessment.
Animals
;
DNA, Mitochondrial/genetics*
;
Humans
;
Male
;
DNA Copy Number Variations
;
Female
;
Fatty Liver/blood*
;
Rats
;
Middle Aged
;
Longitudinal Studies
;
Rats, Sprague-Dawley
;
Adult
;
Japan/epidemiology*
;
Aged
;
Biomarkers/blood*
;
Hep G2 Cells
;
Diet, High-Fat/adverse effects*
10.Development of a new alternative method to inhalation exposure: intratracheal instillation studies using molecular dispersion.
Toshiki MORIMOTO ; Chinatsu NISHIDA ; Hiroto IZUMI ; Taisuke TOMONAGA ; Kazuma SATO ; Yasuyuki HIGASHI ; Ke-Yong WANG ; Takuma KOJIMA ; Kazuo SAKURAI ; Akihiro MORIYAMA ; Jun-Ichi TAKESHITA ; Kei YAMASAKI ; Hidenori HIGASHI ; Kazuhiro YATERA ; Yasuo MORIMOTO
Environmental Health and Preventive Medicine 2025;30():69-69
BACKGROUND:
Organic chemicals have been known to cause allergic diseases such as bronchial asthma and hypersensitivity pneumonitis; however, the possibility that they do not cause irreversible pulmonary fibrosis has not been considered. Polyacrylic acid (PAA), an organic chemical, has caused irreversible progressive pulmonary fibrosis in exposed workers, indicating its potential to induce pulmonary inflammation and fibrosis. Although intratracheal instillation studies are commonly used for evaluating lung pathology, traditional methods face challenges with chemical substances, particularly nanoparticles, which tend to aggregate in suspension and prevent uniform pulmonary distribution. Such aggregation alters the qualitative and quantitative responses to lung injury, limiting accurate assessment of lung pathology. To overcome this limitation, we developed a 'molecular dispersion method' that uses pH modification to negative charges to PAA particles, maintaining their dispersion. Using this method, we investigated the effects of PAA on pulmonary inflammation and fibrosis in a rat model.
METHODS:
F344 rats were intratracheally instilled with PAA using molecular dispersion (0.1 mg/rat, 1.0 mg/rat), PAA without molecular dispersion (1.0 mg/rat), and normal saline (control group). Rats were sacrificed at 3 days, 1 week, 1 month, 3 months, and 6 months after exposure to examine inflammatory and fibrotic responses.
RESULTS:
PAA caused persistent increases in neutrophil influx in the bronchoalveolar lavage fluid (BALF) from 3 days to 1 month following instillation. In histopathological findings, the group with molecular dispersion had almost no inflammatory masses in the lung tissue compared to the group without molecular dispersion, and exhibited relatively uniform dispersion.
CONCLUSION
Intratracheal instillation of dispersed PAA induced neutrophil inflammation and fibrosis in the rat lung, suggesting that PAA might have pulmonary inflammogenicity and fibrogenicity. Intrapulmonary dispersion of PAA particles following intratracheal instillation studies using the molecular dispersion method was similar to that following inhalation studies.
Animals
;
Rats, Inbred F344
;
Acrylic Resins/adverse effects*
;
Rats
;
Inhalation Exposure/adverse effects*
;
Male
;
Pulmonary Fibrosis/pathology*
;
Pneumonia/pathology*
;
Lung/pathology*
;
Bronchoalveolar Lavage Fluid/cytology*

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