Name: a pleural effusion model in rats by intratracheal instillation of polyacrylate/nanosilica
Uploaded: 2019-04-12T13:00:00
Description: Watch this Scientific Journal Video about A Pleural Effusion Model in Rats by Intratracheal Instillation of Polyacrylate/Nanosilica at JoVE.com

The present study and production to this article were funded by the National Natural Science Foundation of China (Grant 81773373, 81172614 and Grant 81441089).&#160;We thank Dr. Jin Yan&#160;and Dr. Pan Yujie, of Department of Emergency, Beijing Chaoyang Hospital,&#160;and Dr. Qu Peng of Department of Ultrasound Medicine, Beijing Chaoyang Hospital&#160;for&#160;helping with the video production.&#160;

The study followed guidelines of Capital Medical University (Beijing, P.R China) for the care and use of experimental animals. All procedures were approved by the Animal Ethical Committee of Capital Medical University in China.
1. Experimental preparations
NOTE: Acclimate the female specific pathogen-free Wistar rats (weight: 200 &#177; 10 g) to the experimental environments for a week before administration (Environmental conditions: light/dark:12h/12h, temperature 22...

<ol>
	<li>Stathopoulos, G. T., 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=Nuclear+factor-kappaB+affects+tumor+progression+in+a+mouse+model+of+malignant+pleural+effusion.">Nuclear factor-kappaB affects tumor progression in a mouse model of malignant pleural effusion.</a> American Journal of Respiratory Cell and Molecular Biology. 34 (2), 142-150 (2006).</li><li>Shen, 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+dosage-toxicity-efficacy+relationship+of+kansui+and+licorice+in+malignant+pleural+effusion+rats+based+on+factor+analysis.">The dosage-toxicity-efficacy relationship of kansui and licorice in malignant pleural effusion rats based on factor analysis.</a> Journal of Ethnopharmacology. 186, 251-256 (2016).</li><li>Nel, A., Xia, T., M&#228;dler, L., Li, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toxic+potential+of+materials+at+the+nanolevel.">Toxic potential of materials at the nanolevel.</a> Science. 311 (5761), 622-627 (2006).</li><li>Maynard, A. D., 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=Safe+handling+of+nanotechnology.">Safe handling of nanotechnology.</a> Nature. 444 (7117), 267-269 (2006).</li><li>Duan, 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=Toxic+effects+of+silica+nanoparticles+on+zebrafish+embryos+and+larvae.">Toxic effects of silica nanoparticles on zebrafish embryos and larvae.</a> PLoS One. 8 (9), 74606 (2013).</li><li>Skuland, T., Ovrevik, J., L&#229;g, M., Schwarze, P., Refsnes, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silica+nanoparticles+induce+cytokine+responses+in+lung+epithelial+cells+through+activation+of+a+p38/TACE/TGF-&#945;/EGFR-pathway+and+NF-&#954;&#914;+signaling.">Silica nanoparticles induce cytokine responses in lung epithelial cells through activation of a p38/TACE/TGF-&#945;/EGFR-pathway and NF-&#954;&#914; signaling.</a> Toxicology and Applied Pharmacology. 279 (1), 76-86 (2014).</li><li>Oberd&#246;rster, G., Oberd&#246;rster, E., Oberd&#246;rster, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanotoxicology:+an+emerging+discipline+evolving+from+studies+of+ultrafine+particles.">Nanotoxicology: an emerging discipline evolving from studies of ultrafine particles.</a> Environmental Health Perspectives. 113 (7), 823-839 (2005).</li><li>Song, Y., Li, X., Du, X. <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+nanoparticles+is+related+to+pleural+effusion,+pulmonary+fibrosis+and+granuloma.">Exposure to nanoparticles is related to pleural effusion, pulmonary fibrosis and granuloma.</a> European Respiratory Journal. 34 (3), 559-567 (2009).</li><li>Song, 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=Nanomaterials+in+humans:+identification,+characteristics,+and+potential+damage.">Nanomaterials in humans: identification, characteristics, and potential damage.</a> Toxicologic Pathology. 39 (5), 841-849 (2011).</li><li>Zhu, 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=Polyacrylate/nanosilica+causes+pleural+and+pericardial+effusion,+and+pulmonary+fibrosis+and+granuloma+in+rats+similar+to+those+observed+in+exposed+workers.">Polyacrylate/nanosilica causes pleural and pericardial effusion, and pulmonary fibrosis and granuloma in rats similar to those observed in exposed workers.</a> International Journal of Nanomedicine. 11, 1593-1605 (2016).</li><li>Havelock, T., 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=Pleural+procedures+and+thoracic+ultrasound:+British+Thoracic+Society+Pleural+Disease+Guideline+2010.">Pleural procedures and thoracic ultrasound: British Thoracic Society Pleural Disease Guideline 2010.</a> Thorax. 65, 61-76 (2010).</li><li>Jha, A., Ullah, E., Gupta, P., Gupta, G., Saud, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonography+of+multifocal+hydatidosis+involving+lung+and+liver+in+a+female+child.">Sonography of multifocal hydatidosis involving lung and liver in a female child.</a> Journal of Medical Ultrasound. 40 (4), 471-474 (2013).</li><li>Hikaru, 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=Histological+analysis+of+70-nm+silica+particles-induced+chronic+toxicity+in+rats.">Histological analysis of 70-nm silica particles-induced chronic toxicity in rats.</a> European Journal of Pharmaceutics and Biopharmaceutics. 72, 626-629 (2009).</li><li>Sun, L., 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=Cytotoxicity+and+mitochondrial+damage+caused+by+silica+nanoparticles.">Cytotoxicity and mitochondrial damage caused by silica nanoparticles.</a> Toxicology in Vitro. 25, 1619-1629 (2011).</li><li>Hikaru, 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=Silica+nanoparticles+as+hepatotoxicants.">Silica nanoparticles as hepatotoxicants.</a> European Journal of Pharmaceutics and Biopharmaceutics. 72, 496-501 (2009).</li><li>Liu, T. I., 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=Single+and+repeated+dose+toxicity+of+mesoporous+hollow+silica+nanoparticles+in+intravenously+exposed+mice.">Single and repeated dose toxicity of mesoporous hollow silica nanoparticles in intravenously exposed mice.</a> Biomaterials. 32, 1657-1668 (2011).</li><li>Ding, M., 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=Diseases+caused+by+silica:+Mechanisms+of+injury+and+disease+development.">Diseases caused by silica: Mechanisms of injury and disease development.</a> International Immunopharmacology. 2, 173-182 (2002).</li><li>Shen, 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+dosage-toxicity-efficacy+relationship+of+kansui+and+licorice+in+malignant+pleural+effusion+rats+based+on+factor+analysis.">The dosage-toxicity-efficacy relationship of kansui and licorice in malignant pleural effusion rats based on factor analysis.</a> Journal of Ethnopharmacology. 186, 251-256 (2016).</li><li>Ji, J. 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=Twenty-eight-day+inhalation+toxicity+study+of+silver+nanoparticles+in+Sprague-Dawley+rats.">Twenty-eight-day inhalation toxicity study of silver nanoparticles in Sprague-Dawley rats.</a> Inhalation Toxicology. 19 (10), 857-871 (2007).</li></ol>

Sonography is the most convenient tool for determining pulmonary diseases, due to its excellent sensitivity to the free fluid in the pleural cavity11. That is because sonography can immediately detect the contrast in acoustic impedance of air and fluids in the lung12. Besides, sonography is more flexible in a small animal&#39;s model than CT. Nevertheless, the air in the lung reflected the sound wave and impeded from observing the intrapulmonary changes after nanoparticles ...

Pleural effusion is a very common clinical manifestation of pulmonary diseases with a variety of causes. Having a useful animal pleural effusion model is very important to study these pulmonary diseases, the roles of the two pleural membrane layers, the mechanisms of pleural effusion, and its treatment. However, some reported pleural effusion models mainly focus on the malignant pleural effusion or biological factors rather than the nanoparticles in the environment1,2. Here, we introduce a new model of pleural effusion that is simple, safe and effective.
With the development of nanotechnology and the extensive use of nanoproducts, there is a concern about the potential hazards of nanomaterials to the environment and the human health3,4. Nanomaterials introduce risk factors and potentially lead to novel hazards within the workplace or through environmental contamination. In vitro and in vivo studies show that nanomaterials can result in multi-organ damage to the lungs, the heart, the liver, the kidney, and the nervous system, as well as the reproductive and immune systems5,6. Additionally, some studies reported that the specific toxicity of nanomaterials was due to their unique physicochemical properties3,4,7.
We have reported that a group of workers with occupational exposure to nanomaterials clinically presented with pleural and pericardial effusion, pulmonary fibrosis and granuloma8,9. Silica nanoparticles were isolated in these patients&#39; pleural effusion9. In order to reproduce and verify the pleural effusion induced by the inhaled nanoparticles in human, we conducted the experiment by instilling the polyacrylate/nanosilica (PA/NPSi) via the respiratory tract in rats, which mimicked human respiration in a real environment, and found that intratracheal instillation of PA/NPSi could result in pleural effusion in rats. Here, we introduce how to make pleural effusion in rats by intratracheal instillation of PA/NPSi, and how to isolate nanoparticles in the pleural effusion. This model may be useful for the further study of nanotoxicology and pleural effusion diseases.

<table border="0" cellpadding="0" cellspacing="0" style="width:843px;" width="843">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">Acuson S2000 Color Doppler ultrasound system</td>
			<td style="width:196px;">Siemens Medical Solutions, Mountain View ,CA</td>
			<td style="width:160px;"></td>
			<td style="width:260px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">&#160;Polyacrylate/nanosilica</td>
			<td style="width:196px;">Fudan University,Shanghai, China</td>
			<td style="width:160px;"></td>
			<td>made by order with nanosilica(20&#177;5)nm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">10% chloral hydrate</td>
			<td style="width:196px;">Beijing Chemical Works</td>
			<td style="width:160px;">302-17-0</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">Transmission electron microscope&#160;</td>
			<td style="width:196px;">JEM-1400Plus&#65292;JEOL Ltd., Japan.</td>
			<td style="width:160px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">Light speed 16 spiral computed tomography</td>
			<td style="width:196px;">GE Healthcare, US</td>
			<td style="width:160px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:227px;">Specific pathogen-free Wistar</td>
			<td style="width:196px;">Animal Center of Lianhelihua (Beijing, China)</td>
			<td style="width:160px;"></td>
			<td>Wistar rats</td>
		</tr>
	</tbody>
</table>

a pleural effusion model in rats by intratracheal instillation of polyacrylate/nanosilica

Pleural effusion is a prevalent clinical finding of many pulmonary diseases. Having a useful animal pleural effusion model is very important to study these pulmonary diseases. Previous pleural effusion models paid more attention to biological factors rather than nanoparticles in the environment. Here, we introduce a model to make pleural effusion in rats by intratracheal instillation of polyacrylate/nanosilica, and a method of nanoparticle isolation in the pleural effusion. By intratracheal instillation of polyacrylate/nanosilica with concentrations of 3.125, 6.25 and 12.5 mg/kg&#8729;mL, the pleural effusion in rats presented on day 3, peaked at days 7-10 in 6.25 and 12.5 mg/kg&#8729;mL groups, then slowly decreased and disappeared on day 14. When the concentration of polyacrylate/nanosilica increased, the pleural effusion is produced more and faster. This pleural fluid was detected by ultrasound examination or CT chest scanning and confirmed by dissection of rats. Silica nanoparticles were observed in the rats' pleural effusion by transmission electron microscope. These results showed that the exposure to polyacrylate/nanosilica leads to the induction of pleural effusion, which was consistent with our previous report in humans. Additionally, this model is beneficial for the further study of nanotoxicology and the pleural effusion diseases.

Using a thoracic ultrasound, we found no pleural effusions on day 1 in all groups. However, on day 3, the pleural effusion appeared in the 6.25 and 12.5 mg/kg&#8729;mL groups. The effusion was mainly in the right costal phrenic angle, while the pericardial effusion only presented in 12.5 mg/kg&#8729;mL group. Furthermore, on day 7, both pleural effusion (Video 1) and pericardial effusion (Video 2) were detected in 6.25 mg/kg&#8729;mL group (<strong class=...

Watch this Scientific Journal Video about A Pleural Effusion Model in Rats by Intratracheal Instillation of Polyacrylate/Nanosilica at JoVE.com

A Pleural Effusion Model in Rats by Intratracheal Instillation of Polyacrylate/Nanosilica

Here, we present a protocol to construct a pleural effusion model in rats by intratracheal instillation of polyacrylate/nanosilica.

Pleural effusion is a prevalent clinical finding of many pulmonary diseases. Having a useful animal pleural effusion model is very important to study ...

This method can provide insight into the toxicity of nanomaterials and can be applied for the study of pulmonary toxicity. This technique was derived to study the effects of polyacrylate/nanosilica-induced pleural effusion. Before beginning the instillation, sonicate a fresh, 10-milliliter, polyacrylate/nanosilica suspension in normal saline for 20 to 30 minutes, followed by 10 minutes of vortexing, before diluting the suspension to 3.125, 6.25, and 12.5 milligram per milliliter concentrations.Next, confirm a lack of response to toe pinch in an anesthetized rat, and fix the front teeth of the animal to the board with a piece of nylon string. Using forceps and a frontal lets, gently open the mouth to visualize the fissure of glottis, and insert a fine tube into the bilateral bronchus. Then, instill 0.5 milliliters of the polyacrylate/nanosilica particles through the tube into the lungs, and place the rat in the supine position with monitoring until full recovery.On days one, three, seven, and 14 after instillation, use an electric shaver to remove the hair from the chest and upper abdomen of each anesthetized rat, and place the rat on the mounting plate of an ultrasound system with a linear array transducer in the supine position. Apply ultrasound gel to the exposed skin, and place the transducer on the intercostal space and subcostal area to detect the pleural fluid. In order to detect the effusion accurately, select the left and right lateral positions to perform an ultrasound examination.On day seven, both pleural effusion and pericardial effusion are detected in the 6.25 milligram per kilogram per milliliter instilled group. On day seven and 14, CT chest scans of the 12.5 milligram per kilogram per milliliter instilled animals are abnormal at the blunt posterior costophrenic angle, hinting at a small amount of pleural effusion. Transmission electron microscopy of pleural effusion samples reveals nanosilica nanoparticles individually and in clusters with a morphology consistent with that observed for nanoparticles within the prepared suspension.The most important thing is to remember to visualize the fissure of the glottis and to insert a fine tube into the bilateral bronchus. The nanoparticles can also be instilled by inhalation or intravenous injection, as both methods have been performed in previous studies. This technique is useful for studying the development of pleural effusion.

a-pleural-effusion-model-rats-intratracheal-instillation

Research

JoVE Journal

Medicine

A Novel Surgical Approach for Intratracheal Administration of Bioactive Agents in a Fetal Mouse Model

Prenatal pulmonary delivery of cells, genes or pharmacologic agents could provide the basis for new therapeutic strategies for a variety of genetic and acquired diseases. Apart from congenital or inherited abnormalities with the requirement for long-term expression of the delivered gene, several non-inherited perinatal conditions, where short-term gene expression or pharmacological intervention is sufficient to achieve therapeutic effects, are considered as potential future indications for this kind of approach. Candidate diseases for the application of short-term prenatal therapy could be the transient neonatal deficiency of surfactant protein B causing neonatal respiratory distress syndrome1,2 or hyperoxic injuries of the neonatal lung3. Candidate diseases for permanent therapeutic correction are Cystic Fibrosis (CF)4, genetic variants of surfactant deficiencies5 and &alpha;1-antitrypsin deficiency6.
Generally, an important advantage of prenatal gene therapy is the ability to start therapeutic intervention early in development, at or even prior to clinical manifestations in the patient, thus preventing irreparable damage to the individual. In addition, fetal organs have an increased cell proliferation rate as compared to adult organs, which could allow a more efficient gene or stem cell transfer into the fetus. Furthermore, in utero gene delivery is performed when the individual's immune system is not completely mature. Therefore, transplantation of heterologous cells or supplementation of a non-functional or absent protein with a correct version should not cause immune sensitization to the cell, vector or transgene product, which has recently been proven to be the case with both cellular and genetic therapies7.
In the present study, we investigated the potential to directly target the fetal trachea in a mouse model. This procedure is in use in larger animal models such as rabbits and sheep8, and even in a clinical setting9, but has to date not been performed before in a mouse model. When studying the potential of fetal gene therapy for genetic diseases such as CF, the mouse model is very useful as a first proof-of-concept because of the wide availability of different transgenic mouse strains, the well documented embryogenesis and fetal development, less stringent ethical regulations, short gestation and the large litter size.
Different access routes have been described to target the fetal rodent lung, including intra-amniotic injection10-12, (ultrasound-guided) intrapulmonary injection13,14 and intravenous administration into the yolk sac vessels15,16 or umbilical vein17. Our novel surgical procedure enables researchers to inject the agent of choice directly into the fetal mouse trachea which allows for a more efficient delivery to the airways than existing techniques18.

We developed a novel surgical approach for intratracheal administration of bioactive agents into the mouse fetus. The delivery route is more efficient in targeting the fetal mouse lungs than the commonly used intra-amniotic injection. This procedure has to date not been described in a mouse model.

Prenatal pulmonary delivery of cells, genes or pharmacologic agents could provide the basis for new therapeutic strategies for a variety of genetic and ...

A Contusion Model of Severe Spinal Cord Injury in Rats

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is described to obtain a consistent model of severe SCI. Use of a stereotactic frame and computer controlled impactor allows for creation of reproducible injury. Hypothermia and urinary tract infection pose significant challenges in the post-operative period. Careful monitoring of animals with daily weight recording and bladder expression allows for early detection of post-operative complications. The functional results of this contusion model are equivalent to transection models. The contusion model can be utilized to evaluate the efficacy of both neuroprotective and neuroregenerative approaches.

A contusion model of severe spinal cord injury is described. Detailed pre-operative, operative and post-operative steps are described to obtain a consistent model.

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is ...

Intubation-mediated Intratracheal (IMIT) Instillation: A Noninvasive, Lung-specific Delivery System

Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences between the murine and human respiratory systems, especially in their upper respiratory tracts (URT). In some models, these differences in the murine nasal cavity can have a significant impact on disease progression and presentation in the lower respiratory tract (LRT) when using intranasal instillation techniques, potentially limiting the usefulness of the mouse model to study these diseases. For these reasons, it would be advantageous to develop a technique to instill bacteria directly into the mouse lungs in order to study LRT disease in the absence of involvement of the URT. We have termed this lung specific delivery technique intubation-mediated intratracheal (IMIT) instillation. This noninvasive technique minimizes the potential for instillation into the bloodstream, which can occur during more invasive traditional surgical intratracheal infection approaches, and limits the possibility of incidental digestive tract delivery. IMIT is a two-step process in which mice are first intubated, with an intermediate step to ensure correct catheter placement into the trachea, followed by insertion of a blunt needle into the catheter to mediate direct delivery of bacteria into the lung. This approach facilitates a &#62;98% efficacy of delivery into the lungs with excellent distribution of reagent throughout the lung. Thus, IMIT represents a novel approach to study LRT disease and therapeutic delivery directly into the lung, improving upon the ability to use mice as surrogates to study human respiratory disease. Furthermore, the accuracy and reproducibility of this delivery system also makes it amenable to Good Laboratory Practice Standards (GLPS), as well as delivery of a wide range of reagents which require high efficiency delivery to the lung.

Intubation-mediated Intratracheal IMIT Instillation: A Noninvasive, Lung-specific Delivery System

Intubation-mediated intratracheal (IMIT) instillation of reagents is an excellent, noninvasive method for studying respiratory disease, as well as a method for instilling therapeutic reagents directly into the lung. It is a rapid and highly reproducible method which is suitable for preclinical testing.

Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences ...

Retroductal Submandibular Gland Instillation and Localized Fractionated Irradiation in a Rat Model of Salivary Hypofunction

Normal tissues that lie within the portals of radiation are inadvertently damaged. Salivary glands are often injured during head and neck radiotherapy. Irreparable cell damage results in a chronic loss of salivary function that impairs basic oral activities, and increases the risk of oral infections and dental caries. Salivary hypofunction and its complications gravely impact a patient's comfort. Current symptomatic management of the condition is ineffective, and newer therapies to assuage the condition are needed. 
Salivary glands are exocrine glands, which expel their secretions into the mouth via excretory ducts. Cannulation of these ducts provides direct access to the glands. Retroductal delivery of a contrast agent to major salivary glands is a routine out-patient procedure for diagnostic imaging. Using a similar procedure, localized treatment of the glands is feasible. However, performing this technique in preclinical studies with small animals poses unique challenges. In this study we describe the technique of retroductal administration in rat submandibular glands, a procedure that was refined in Dr. Bruce Baum's laboratory (NIH)1, and lay out a procedure for local gland irradiation.

Salivary gland hypofunction, a major adverse effect of head and neck radiotherapy diminishes a patient's quality of life. The demonstration of efficacy of new therapies in animal models is a prerequisite before clinical transition. This protocol describes retroductal administration and local irradiation of rat submandibular glands.

Normal tissues that lie within the portals of radiation are inadvertently damaged. Salivary glands are often injured during head and neck radiotherapy. ...

A Model of Glaucoma Induced by Circumlimbal Suture in Rats and Mice

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known risk factor for glaucoma. This protocol demonstrates a step-by-step guide on this technique in Long Evans rats and C57BL/6 mice. Under general anesthesia, a "purse-string" suture is applied on the conjunctiva, around the equator and behind the limbus of the eye. The fellow eye serves as an untreated control. Over the duration of our study, which was a period of 8 weeks for rats and 12 weeks for mice, IOP remained elevated, as measured regularly by rebound tonometry in conscious animals without topical anesthesia. In both species, the sutured eyes showed electroretinogram features consistent with preferential inner retinal dysfunction. Optical coherence tomography showed selective thinning of the retinal nerve fiber layer. Histology of the rat retina in cross-section found reduced cell density in the ganglion cell layer, but no change in other cellular layers. Staining of flat-mounted mouse retinae with a ganglion cell specific marker (RBPMS) confirmed ganglion cell loss. The circumlimbal suture is a simple, minimally invasive and cost-effective way to induce ocular hypertension that leads to ganglion cell injury in both rats and mice.

Chronic ocular hypertension is induced by applying a circumlimbal suture in rats and mice, leading to functional and structural deterioration of the retinal ganglion cells consistent with glaucoma.

The circumlimbal suture is a technique for inducing experimental glaucoma in rodents by chronically elevating intraocular pressure (IOP), a well-known ...

Inducing Acute Lung Injury in Mice by Direct Intratracheal Lipopolysaccharide Instillation

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. Various approaches have been described, such as the inhalation of aerosolized LPS as well as nasal or intratracheal instillation. The presented protocol describes a detailed step-by-step procedure to induce ALI in mice by direct intratracheal LPS instillation and perform FACS analysis of blood samples, bronchoalveolar lavage (BAL) fluid, and lung tissue. After intraperitoneal sedation, the trachea is exposed and LPS is administered via a 22 G venous catheter. A robust and reproducible inflammatory reaction with leukocyte invasion, upregulation of proinflammatory cytokines, and disruption of the alveolo-capillary barrier is induced within hours to days, depending on the LPS dosage used. Collection of blood samples, BAL fluid, and lung harvesting, as well as the processing for FACS analysis, are described in detail in the protocol. Although the use of the sterile LPS is not suitable to study pharmacologic interventions in infectious diseases, the described approach offers minimal invasiveness, simple handling, and good reproducibility to answer mechanistic immunological questions. Furthermore, dose titration as well as the use of alternative LPS preparations or mouse strains allow modulation of the clinical effects, which can exhibit different degrees of ALI severity or early vs. late onset of disease symptoms.

Presented here is a step-by-step procedure to induce acute lung injury in mice by direct intratracheal lipopolysaccharide instillation and to perform FACS analysis of blood samples, bronchoalveolar lavage fluid, and lung tissue. Minimal invasiveness, simple handling, good reproducibility, and titration of disease severity are advantages of this approach.

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. ...

Osteoarthritis Pain Model Induced by Intra-Articular Injection of Mono-Iodoacetate in Rats

The current animal models of osteoarthritis (OA) can be divided into spontaneous models and induced models, both of which aim to simulate the pathophysiological changes of human OA. However, as the main symptom in the late stage of OA, pain affects the patients&#39; daily life, and there are not many available models. The mono-iodoacetate (MIA)-induced model is the most widely used OA pain model, mainly used in rodents. MIA is an inhibitor of glyceraldehyde-3-phosphate dehydrogenase, which causes chondrocyte death, cartilage degeneration, osteophyte, and measurable changes in animal behavior. Besides, expression changes of matrix metalloproteinase (MMP) and pro-inflammatory cytokines (IL1 &#946; and TNF &#945;) can be detected in the MIA-induced model. Those changes are consistent with OA pathophysiological conditions in humans, indicating that MIA can induce a measurable and successful OA pain model. This study aims to describe the methodology of intra-articular injection of MIA in rats and discuss the resulting pain-related behaviors and histopathological changes.

This study describes the method of intra-articular injection of mono-iodoacetate in rats and discusses the resulting pain-related behaviors and histopathological changes, which provide references for future applications.

The current animal models of osteoarthritis (OA) can be divided into spontaneous models and induced models, both of which aim to simulate the ...

Intratracheal Instillation of Stem Cells in Term Neonatal Rats

Prolonged exposure to high concentrations of oxygen leads to inflammation and acute lung injury, which is similar to human bronchopulmonary dysplasia (BPD). In premature infants, BPD is a major complication despite early use of surfactant therapy, optimal ventilation strategies, and noninvasive positive pressure ventilation. Because pulmonary inflammation plays a crucial role in the pathogenesis of BPD, corticosteroid use is one potential treatment to prevent it. Nevertheless, systemic corticosteroid treatment is not usually recommended for preterm infants due to long-term adverse effects. Preclinical studies and human phase I clinical trials demonstrated that use of mesenchymal stromal cells (MSCs) in hyperoxia-induced lung injuries and in preterm infants is safe and feasible. Intratracheal and intravenous MSC transplantation has been shown to protect against neonatal hyperoxic lung injury. Therefore, intratracheal administration of stem cells and combined surfactant and glucocorticoid treatment has emerged as a new strategy to treat newborns with respiratory disorders. The developmental stage of rat lungs at birth is equivalent to that in human lungs at 26&#8722;28 week of gestation. Hence, newborn rats are appropriate for studying intratracheal administration to preterm infants with respiratory distress to evaluate its efficacy. This intratracheal instillation technique is a clinically viable option for delivery of stem cells and drugs into the lungs.

Described is a protocol for performing intratracheal transplantation of mesenchymal stromal cells (MSCs) through intratracheal injection in term neonatal rats. This technique is a clinically viable option for delivery of stem cells and drugs into neonatal rat lungs to evaluate their efficacy.

Prolonged exposure to high concentrations of oxygen leads to inflammation and acute lung injury, which is similar to human bronchopulmonary dysplasia ...

A Minimally Invasive Method for Intratracheal Instillation of Drugs in Neonatal Rodents to Treat Lung Disease

Treatment of neonatal rodent with drugs instilled directly into the trachea could serve as a valuable tool to study the impact of a locally administered drug. This has direct translational impact because surfactant and drugs are administered locally into the lungs. Though the literature has many publications describing minimally invasive transoral intubation of adult mice and rats in therapeutic experiments, this approach in neonatal rat pups is lacking. The small size of orotracheal region/pharynx in the pups makes visualization of laryngeal lumen (vocal cords) difficult, contributing to the variable success rate of intratracheal drug delivery. We hereby demonstrate effective oral intubation of neonatal rat pup - a technique that is non-traumatic and minimally-invasive, so that it can be used for serial administration of drugs. We used an operating otoscope with an illumination system and a magnifying lens to visualize the tracheal opening of the rat neonates. The drug is then instilled using a 1 mL syringe connected to a pipette tip. The accuracy of the delivery method was demonstrated using Evans blue dye administration. This method is easy to get trained in and could serve as an effective way to instill drugs into trachea. This method could also be used for administration of inoculum or agents to simulate disease conditions in animals and, also, for cell-based treatment strategies for various lung diseases.

This technique of instilling drugs directly into the trachea of neonatal rodents is important in studying the impact of locally administered drugs or biologicals on neonatal lung diseases. Additionally, this method can also be used for inducing lung injury in animal models.

Treatment of neonatal rodent with drugs instilled directly into the trachea could serve as a valuable tool to study the impact of a locally administered ...

A Model of Reverse Vascular Remodeling in Pulmonary Hypertension Due to Left Heart Disease by Aortic Debanding in Rats

Pulmonary hypertension due to left heart disease (PH-LHD) is the most common form of PH, yet its pathophysiology is poorly characterized than pulmonary arterial hypertension (PAH). As a result, approved therapeutic interventions for the treatment or prevention of PH-LHD are missing. Medications used to treat PH in PAH patients are not recommended for treatment of PH-LHD, as reduced pulmonary vascular resistance (PVR) and increased pulmonary blood flow in the presence of increased left-sided filling pressures may cause left heart decompensation and pulmonary edema. New strategies need to be developed to reverse PH in LHD patients. In contrast to PAH, PH-LHD develops due to increased mechanical load caused by congestion of blood into the lung circulation during left heart failure. Clinically, mechanical unloading of the left ventricle (LV) by aortic valve replacement in aortic stenosis patients or by implantation of LV assist devices in end-stage heart failure patients normalizes not only pulmonary arterial and right ventricular (RV) pressures but also PVR, thus providing indirect evidence for reverse remodeling in the pulmonary vasculature. Using an established rat model of PH-LHD due to left heart failure triggered by pressure overload with subsequent development of PH, a model is developed to study the molecular and cellular mechanisms of this physiological reverse remodeling process. Specifically, an aortic debanding surgery was performed, which resulted in reverse remodeling of the LV myocardium and its unloading. In parallel, complete normalization of RV systolic pressure and significant but incomplete reversal of RV hypertrophy was detectable. This model may present a valuable tool to study the mechanisms of physiological reverse remodeling in the pulmonary circulation and the RV, aiming to develop therapeutic strategies for treating PH-LHD and other forms of PH.

The present protocol describes a surgical procedure to remove ascending-aortic banding in a rat model of pulmonary hypertension due to left heart disease. This technique studies endogenous mechanisms of reverse remodeling in the pulmonary circulation and the right heart, thus informing strategies to reverse pulmonary hypertension and/or right ventricular dysfunction.

Pulmonary hypertension due to left heart disease (PH-LHD) is the most common form of PH, yet its pathophysiology is poorly characterized than pulmonary ...