Name: establishing a silicosis rat model via exposure of whole-body to respirable silica
Uploaded: 2022-10-28T14:30:00
Description: Watch this Scientific Journal Video about Establishing a Silicosis Rat Model via Exposure of Whole-Body to Respirable Silica at JoVE.com

This work was funded by the National Natural Science Foundation of China (82003406), the Natural Science Foundation of Hebei Province (H2022209073), and the Science and Technology Project of Hebei Education Department (ZD2022127).

All animal experiments were conducted according to the United States National Institutes of Health Guide for the Care and Use of Laboratory Animals and approved by the Committee on the Ethics of North China University of Science and Technology (protocol code LX2019033 and 2019-3-3 of approval). Male Wistar rats, 3 weeks of age, were used for the present study. All rats were kept in static cages with wood shavings. The animals were maintained in a 12 h/12 h light/dark cycle, and were provided with food and water ad li...

<ol>
	<li>Li, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+burden+of+pneumoconiosis+in+China:+an+analysis+from+the+Global+Burden+of+Disease+Study.">The burden of pneumoconiosis in China: an analysis from the Global Burden of Disease Study.</a> BMC Public Health. 22 (1), 1114 (2019).</li><li>The Lancet Respiratory Medicine. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+world+is+failing+on+silicosis.">The world is failing on silicosis.</a> The Lancet. Respiratory Medicine. 7 (4), 283 (2019).</li><li>Li, T., Yang, X., Xu, H., Liu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+identification,+accurate+diagnosis,+and+treatment+of+silicosis.">Early identification, accurate diagnosis, and treatment of silicosis.</a> Canadian Respiratory Journal. 3769134, (2022).</li><li>Adamcakova, J., Mokra, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+insights+into+pathomechanisms+and+treatment+possibilities+for+lung+silicosis.">New insights into pathomechanisms and treatment possibilities for lung silicosis.</a> International Journal of Molecular Sciences. 22 (8), 4162 (2021).</li><li>Li, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thalidomide+alleviates+pulmonary+fibrosis+induced+by+silica+in+mice+by+inhibiting+ER+stress+and+the+TLR4-NF-&#954;B+pathway.">Thalidomide alleviates pulmonary fibrosis induced by silica in mice by inhibiting ER stress and the TLR4-NF-&#954;B pathway.</a> International Journal of Molecular Sciences. 23 (10), 5656 (2022).</li><li>Zhang, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exosomes+derived+from+bone+marrow+mesenchymal+stem+cells+reverse+epithelial-mesenchymal+transition+potentially+via+attenuating+Wnt/&#946;-catenin+signaling+to+alleviate+silica-induced+pulmonary+fibrosis.">Exosomes derived from bone marrow mesenchymal stem cells reverse epithelial-mesenchymal transition potentially via attenuating Wnt/&#946;-catenin signaling to alleviate silica-induced pulmonary fibrosis.</a> Toxicology Mechanisms and Methods. 31 (9), 655-666 (2021).</li><li>Li, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Acetyl-Seryl-Asparyl-Lysyl-Proline+regulates+lung+renin+angiotensin+system+to+inhibit+epithelial-mesenchymal+transition+in+silicotic+mice.">N-Acetyl-Seryl-Asparyl-Lysyl-Proline regulates lung renin angiotensin system to inhibit epithelial-mesenchymal transition in silicotic mice.</a> Toxicology and Applied Pharmacology. 408, 408 (2020).</li><li>Walters, E. H., Shukla, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silicosis:+Pathogenesis+and+utility+of+animal+models+of+disease.">Silicosis: Pathogenesis and utility of animal models of disease.</a> Allergy. 76 (10), 3241-3242 (2021).</li><li>Langley, R. J., Mishra, N. C., Pe&#241;a-Philippides, J. C., Hutt, J. A., Sopori, M. 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L., Dalal, N. S., Irr, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+free+radicals+from+freshly+fractured+silica+dust.+Potential+role+in+acute+silica-induced+lung+injury.">Generation of free radicals from freshly fractured silica dust. Potential role in acute silica-induced lung injury.</a> The American Review of Respiratory Disease. 138 (5), 1213-1219 (1988).</li><li>Khoo, S. Y., Lay, B. P. 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N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histological+quantification+of+chronic+myocardial+infarct+in+rats.">Histological quantification of chronic myocardial infarct in rats.</a> Journal of Visualized Experiments. 118 (118), (2016).</li><li>Zhang, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=silicosis+decreases+bone+mineral+density+in+rats.">silicosis decreases bone mineral density in rats.</a> Toxicology and Applied Pharmacology. 348, 117-122 (2018).</li><li>Zhang, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+the+RAS+axis+alleviates+silicotic+fibrosis+and+Ang+II-induced+myofibroblast+differentiation+via+inhibition+of+the+hedgehog+signaling+pathway.">Targeting the RAS axis alleviates silicotic fibrosis and Ang II-induced myofibroblast differentiation via inhibition of the hedgehog signaling pathway.</a> Toxicology Letters. 313, 30-41 (2019).</li><li>Li, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silica+perturbs+primary+cilia+and+causes+myofibroblast+differentiation+during+silicosis+by+reduction+of+the+KIF3A-repressor+GLI3+complex.">Silica perturbs primary cilia and causes myofibroblast differentiation during silicosis by reduction of the KIF3A-repressor GLI3 complex.</a> Theranostics. 10 (4), 1719-1732 (2020).</li><li>Gao, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulmonary+silicosis+alters+microRNA+expression+in+rat+lung+and+miR-411-3p+exerts+anti-fibrotic+effects+by+inhibiting+MRTF-A/SRF+signaling.+Molecular+therapy.">Pulmonary silicosis alters microRNA expression in rat lung and miR-411-3p exerts anti-fibrotic effects by inhibiting MRTF-A/SRF signaling. Molecular therapy.</a> Nucleic Acids. 20, 851-865 (2020).</li><li>Cai, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+expression+of+lncRNAs+during+silicosis+and+the+role+of+LOC103691771+in+myofibroblast+differentiation+induced+by+TGF-&#946;1.">Differential expression of lncRNAs during silicosis and the role of LOC103691771 in myofibroblast differentiation induced by TGF-&#946;1.</a> Biomedicine &amp; Pharmacotherapy. 125, (2020).</li><li>Cai, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcriptomic+analysis+identifies+upregulation+of+secreted+phosphoprotein+1+in+silicotic+rats.">Transcriptomic analysis identifies upregulation of secreted phosphoprotein 1 in silicotic rats.</a> Experimental and Therapeutic. 21 (6), (2021).</li><li>Li, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minute+cellular+nodules+as+early+lesions+in+rats+with+silica+exposure+via+inhalation.">Minute cellular nodules as early lesions in rats with silica exposure via inhalation.</a> Veterinary Sciences. 9 (6), 251 (2022).</li><li>Mao, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycolytic+reprogramming+in+silica-induced+lung+macrophages+and+silicosis+reversed+by+Ac-SDKP+treatment.">Glycolytic reprogramming in silica-induced lung macrophages and silicosis reversed by Ac-SDKP treatment.</a> International Journal of Molecular Sciences. 22 (18), 10063 (2021).</li><li>Hamilton, R. F., Thakur, S. A., Holian, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silica+binding+and+toxicity+in+alveolar+macrophages.">Silica binding and toxicity in alveolar macrophages.</a> Free Radical Biology and Medicine. 44 (7), 1246-1258 (2008).</li><li>Park, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exposure+to+crystalline+silica,+silicosis,+and+lung+disease+other+than+cancer+in+diatomaceous+earth+industry+workers:+a+quantitative+risk+assessment.">Exposure to crystalline silica, silicosis, and lung disease other than cancer in diatomaceous earth industry workers: a quantitative risk assessment.</a> Occupational and Environmental. 59 (1), 36-43 (2002).</li><li>Honnons, S., Porcher, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+experimental+model+for+silicosis.">In vivo experimental model for silicosis.</a> Journal of Environmental Pathology, Toxicology and. 19 (4), 391-400 (2000).</li><li>Lakatos, H. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oropharyngeal+aspiration+of+a+silica+suspension+produces+a+superior+model+of+silicosis+in+the+mouse+when+compared+to+intratracheal+instillation.">Oropharyngeal aspiration of a silica suspension produces a superior model of silicosis in the mouse when compared to intratracheal instillation.</a> Experimental Lung Research. 32 (5), 181-199 (2006).</li><li>Li, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+suitable+silicosis+mouse+model+was+constructed+by+repeated+inhalation+of+silica+dust+via+nose.">A suitable silicosis mouse model was constructed by repeated inhalation of silica dust via nose.</a> Toxicology Letters. 353, 1-12 (2021).</li><li>Hoy, R. F., Chambers, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silica-related+diseases+in+the+modern+world.">Silica-related diseases in the modern world.</a> Allergy. 75 (11), 2805-2817 (2020).</li><li>Davis, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenesis+of+silicosis:+current+concepts+and+hypotheses.">Pathogenesis of silicosis: current concepts and hypotheses.</a> Lung. 164 (3), 139-154 (1986).</li><li>Moss, O. R., James, R. 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As the leading cause of silicosis, silica plays a decisive role in molding. The silica particles inhaled by patients with pneumoconiosis are fresh, free silica particles produced by mechanical cutting. Silica can generate reactive oxygen species either directly on freshly cleaved particle surfaces or indirectly through its effect on the macrophages25. Therefore, the grinding of silica particles is of high importance. In the proposed protocol, silica was ground with agate mortar for more than 90 mi...

Silicosis, which is caused by the inhalation of silica, is the most serious occupational disease in China, accounting for more than 80% of the total number of occupational disease reports every year1. The etiology of silicosis is clear, and it can be prevented and controlled, but no effective treatment method is available2. Many drugs have been proven to be effective in basic studies, but they have imprecise clinical effects3,4. Therefore, the pathological and physiological mechanisms of silicosis still need to be explored.
Many studies have used a one-time infusion of silica into the trachea of rats or mice to investigate the pathogenesis of silicosis5,6. Although these rodent silicotic models could be obtained in a short time7, these methods still had challenges, such as animal trauma and high mortality. Some studies have involved instilling stored silica into the lungs to induce a nonspecific lung reaction, but did not mention silicotic nodules in mice8. Furthermore, away from acute silicosis, chronic exposure to silica in occupational environments induced significantly lower pulmonary inflammation and elevated the levels of anti-apoptotic markers, rather than pro-apoptotic markers, in the lungs9. Therefore, a reliable, reasonable, and repeatable animal model is needed to explore the pathogenesis of silicosis further.
The present study describes a method to mimic the disease process of patients with silicosis through silica inhalation via the whole body, air-delivered particles in an inhalation chamber, which comprised an air-delivered silica generator, a whole-body chamber, and a waste disposal system. This method is simple, easy to operate, and effectively mimics the pathological dynamic evolution process of silicosis. Also, many possible mechanisms and the pathogenesis of silicosis are identified using this method10,11,12. The proposed protocol is anticipated to help further investigations in the related field of silicosis research.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Air detector (compressive atmospheric sampler)</td>
			<td>Qingdao Xuyu Environmental Protection Technology Co. LTD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anatomical table</td>
			<td></td>
			<td></td>
			<td>&#160;No specific brand is recommended.</td>
		</tr>
		<tr>
			<td>Antibody of CD68</td>
			<td>Abcam</td>
			<td>ab201340</td>
			<td></td>
		</tr>
		<tr>
			<td>DAB</td>
			<td>ZSGB-BIO</td>
			<td>ZLI-9018</td>
			<td></td>
		</tr>
		<tr>
			<td>Electric heating air-blowing drier</td>
			<td>Shanghai Yiheng Scientific Instrument Co., LTD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Electronic balance</td>
			<td>OHRUS</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Embedding machine</td>
			<td>leica</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Exhaust gas discharge device &#160;</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Generator systems&#160;</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gloves (thin laboratory gloves)</td>
			<td>The secco medical</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hematoxylin and eosin</td>
			<td>BaSO Diagnostics Inc.</td>
			<td>BA4025</td>
			<td></td>
		</tr>
		<tr>
			<td>HOPE MED 8050 exposure control apparatus</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Inhalation chamber&#160;</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Injection syringe</td>
			<td></td>
			<td></td>
			<td>&#160;No specific brand is recommended.</td>
		</tr>
		<tr>
			<td>Light microscope&#160;</td>
			<td>olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Object slide</td>
			<td>shitai</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PV-6000 (HRP-conjugated goat anti-mouse IgG polymer)</td>
			<td>Beijing Zhongshan Jinqiao Biotechnology Co. Ltd</td>
			<td>s5631</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon dioxide</td>
			<td>Sigma-Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Slicing machine</td>
			<td>leica</td>
			<td>RM2255</td>
			<td></td>
		</tr>
		<tr>
			<td>Waste gas treatment device</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Wet box</td>
			<td>Cooperative plastic Products Factory</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Xylol</td>
			<td>Tianjin Yongda Chemical Reagent Co., LTD</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

establishing a silicosis rat model via exposure of whole-body to respirable silica

The major cause of silicosis is the inhalation of silica in the occupational environment. Despite some anatomical and physiological differences, rodent models continue to be an essential tool for studying human silicosis. For silicosis, the classic pathological process needs to be inducible via the inhalation of freshly generated quartz particles, which means specifically inducing human occupational disease. This study described a technique to establish and effectively mimic the pathological dynamic evolution process of silicosis. Further, the technique had good repeatability with no surgery involved. The inhalation exposure system was fabricated, validated, and used for toxicology studies on respirable particle inhalation. The critical components were as follows: (1) bulk dry SiO2 powder generator adjusted with an air-flow controller; (2) 0.3 m3 whole-body inhalation exposure chamber accommodating up to 3&#160;adult rats; (3) a monitoring and control system for regulating oxygen concentration, temperature, humidity, and pressure in real-time; and (4) a barrier and waste disposal system for protecting laboratory technicians and the environment. In summary, the present protocol reports the inhalation via the whole body, and the inhalation chamber created a reliable, reasonable, and repeatable rat silicotic model with low mortality, less injury, and more protection.

Using the proposed method, some potential mechanisms and the pathogenesis of silicosis were explored in rats. The schematic of the inhalation chamber is shown in Figure 1. The chamber consisted of an air-delivered silica generator, a whole-body chamber, and a waste disposal system, as previously described17. The pulmonary functions, levels of inflammatory factors in the serum and lung, collagen deposition, and myofibroblast differentiation were reported in the previou...

Watch this Scientific Journal Video about Establishing a Silicosis Rat Model via Exposure of Whole-Body to Respirable Silica at JoVE.com

Establishing a Silicosis Rat Model via Exposure of Whole-Body to Respirable Silica

This study describes a technique to establish a silicosis rat model with the inhalation of silica through the whole body in an inhalation chamber. The rats with silicosis could closely mimic the pathological process of human silicosis in an easy, cost-effective manner with good repeatability.

The major cause of silicosis is the inhalation of silica in the occupational environment. Despite some anatomical and physiological differences, rodent ...

Using this protocol of silicosis rat model, it is possible to closely mimic the pathological process of human silicosis. This technique is easy to perform cost effectively with good repeatability, and there is no trauma to the animal. The established rat model in this study contributes to early identification, accurate diagnosis, and treatment of silicosis.To begin, place the silica particles in an agate mortar and grind for 1.5 hours before each animal exposure. Then weigh 30 grams of the ground silica in an electronic balance and place it in a glass container. Bake at 180 degrees Celsius for six hours in an electric-heating, air-blowing dryer to eliminate pathogens from the surface of the silica particles.Set up the silica exposure controller by connecting the injection and the generator systems. Then place the weighed silica in the generator and confirm that the pipeline connection is proper. The power cord is connected, and the power supply is normal.After ensuring the valves of the inhalation chamber are closed, turn on the exhaust gas discharge device and the air source to confirm that the inside of the shielding cabinet is in a negative pressure state. Check the silica concentration in the cabinet with a calibrated atmospheric sampler following the manufacturer's instructions. For gravimetric determination, use a digital, single-pan, analytical balance and weigh down the silica.Place the rat in the cage, then place 10 rats in the inhalation chamber and close the inhalation compartment and the screened cabinet doors. Then proceed with the silica inhalation experiment as planned. On completion of the experiment, close the mixed gas flow control valve and open the pure gas flow valve to inject the gas into the inhalation chamber.After 20 minutes, close the pure air flow valve. Open the door and take the cage out of the inhalation chamber. Then take the rats out of the cage and take them back to the pathogen-free room.Next, remove the rat rack and the branch pipe components in sequence and place them in the sink for cleaning. After rinsing, close the automatic cleaning valve and open the hatch. Then wipe the inner wall with a clean cloth to dry the tank.Finally, disinfect the tank with 75%ethanol and close the exhaust gate. Next, quickly open the door of the inhalation cabin to evaporate the moisture so that the inside of the inhalation cabin remains dry. The rats exposed to silica for two and 24 weeks revealed alveolar wall thickening after two weeks of silica inhalation, whereas the alveolar structure disappeared, and large areas of fibrosis formed after 24 weeks.Further, the silica particles were seen trapped in the macrophages of the lung lobes observed through a polarized light microscope. Immunohistochemical staining of CD 68 in the lung revealed the dynamic evolution of silicotic nodules from two to 24 weeks. As the exposure time increased, the area of the nodules also gradually increased, and the adjacent silicotic nodules fused into larger nodules.Multiple fibrotic lesions of varying sizes were formed in the lungs of rats exposed to silica compared with the control rats. However, no significant differences in the kidney, liver, and spleen were found between the rats with silicosis and the control. But interestingly, bone loss was observed in rats with silicosis.The most important thing in this protocol is ensuring that the silica is well-ground, and the concentration is constant before starting the procedure.

Research

JoVE Journal

Medicine

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