Name: induction of periodontitis via a combination of ligature and lipopolysaccharide injection in a rat model
Uploaded: 2023-02-17T14:10:00
Description: Watch this Scientific Journal Video about Induction of Periodontitis via a Combination of Ligature and Lipopolysaccharide Injection in a Rat Model at JoVE.com

This work was supported by Fundaci&#243; Universitat-Empresa de les Illes Balears (Proof of concept call 2020), by the Instituto de Salud Carlos III, Ministerio de Econom&#237;a y Competividad, co-funded by the ESF European Social Fund and the ERDF European Regional Development Fund (contract to M.M.B; FI18/00104) and by the Direcci&#243; General d&#39;Investigaci&#243;, Conselleria d&#39;Investigaci&#243;, Govern Balear (contract to M.M.F.C; FPI/040/2020). The authors thank Dr. Anna Tom&#225;s and Maria Tortosa for their help at the experimental surgery and platform of IdISBa. Finally, thanks to ADEMA School of Dentistry for the access to the CBCT scanner.

NOTE: The experimental protocol of the study was approved by the Ethical Committee of Animal Experimentation of the Balearic Islands Health Research Institute (CEEA-UIB; reference number 163/03/21).
1. Animal anesthesia and procedure preparation
<ol>
	<li>Sterilize all surgical instruments (aluminium mouth gags, dental explorer, diamond lance, surgical scissors, microsurgical pliers, a micro needle holder, a hollenback carver, a periosteal microsurgical elevator, and microsu...

<ol>
	<li>Carvalho, J. D. 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=Impact+of+citrus+flavonoid+supplementation+on+inflammation+in+lipopolysaccharide-induced+periodontal+disease+in+mice.">Impact of citrus flavonoid supplementation on inflammation in lipopolysaccharide-induced periodontal disease in mice.</a> Food and Function. 12 (11), 5007-5017 (2021).</li><li>Nazir, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevalence+of+periodontal+disease,+its+association+with+systemic+diseases+and+prevention.">Prevalence of periodontal disease, its association with systemic diseases and prevention.</a> International Journal of Health Sciences. 1 (2), 72-80 (2017).</li><li>Dumitrescu, A. L., El-Aleem, S. A., Morales-Aza, B., Donaldson, L. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+model+of+periodontitis+in+the+rat:+Effect+of+lipopolysaccharide+on+bone+resorption,+osteoclast+activity,+and+local+peptidergic+innervation.">A model of periodontitis in the rat: Effect of lipopolysaccharide on bone resorption, osteoclast activity, and local peptidergic innervation.</a> Journal of Clinical Periodontology. 31 (8), 596-603 (2004).</li><li>Wang, H. 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=Preventive+effects+of+the+novel+antimicrobial+peptide+Nal-P-113+in+a+rat+Periodontitis+model+by+limiting+the+growth+of+Porphyromonas+gingivalis+and+modulating+IL-1&#946;+and+TNF-&#945;+production.">Preventive effects of the novel antimicrobial peptide Nal-P-113 in a rat Periodontitis model by limiting the growth of Porphyromonas gingivalis and modulating IL-1&#946; and TNF-&#945; production.</a> BMC Complementary and Alternative Medicine. 17 (1), 1-10 (2017).</li><li>Guan, J., Zhang, D., Wang, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identifying+periodontitis+risk+factors+through+a+retrospective+analysis+of+80+cases.">Identifying periodontitis risk factors through a retrospective analysis of 80 cases.</a> Pakistan Journal of Medical Sciences. 38 (1), 293-296 (2021).</li><li>Khajuria, D. K., Patil, O. N., Karasik, D., Razdan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+evaluation+of+novel+biodegradable+chitosan+based+metformin+intrapocket+dental+film+for+the+management+of+periodontitis+and+alveolar+bone+loss+in+a+rat+model.">Development and evaluation of novel biodegradable chitosan based metformin intrapocket dental film for the management of periodontitis and alveolar bone loss in a rat model.</a> Archives of Oral Biology. 85, 120-129 (2018).</li><li>Nishida, 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=Bone+resorption+and+local+interleukin-1alpha+and+interleukin-1beta+synthesis+induced+by+Actinobacillus+actinomycetemcomitans+and+Porphyromonas+gingivalis+lipopolysaccharide.">Bone resorption and local interleukin-1alpha and interleukin-1beta synthesis induced by Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis lipopolysaccharide.</a> Journal of Periodontal Research. 36 (1), 1-8 (2001).</li><li>Graves, D. T., Kang, J., Andriankaja, O., Wada, K., Rossa, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+to+study+host-bacteria+interactions+involved+in+periodontitis.">Animal models to study host-bacteria interactions involved in periodontitis.</a> Bone. 23 (1), 1-7 (2008).</li><li>Struillou, X., Boutigny, H., Soueidan, A., Layrolle, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+animal+models+in+periodontology:+a+review.">Experimental animal models in periodontology: a review.</a> The Open Dentistry Journal. 4 (1), 37-47 (2010).</li><li>Mustafa, 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=Induction+of+periodontal+disease+via+retentive+ligature,+lipopolysaccharide+injection,+and+their+combination+in+a+rat+model.">Induction of periodontal disease via retentive ligature, lipopolysaccharide injection, and their combination in a rat model.</a> Polish Journal of Veterinary Sciences. 24 (3), 365-373 (2021).</li><li>Chadwick, J. W., Glogauer, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Robust+ligature-induced+model+of+murine+periodontitis+for+the+evaluation+of+oral+neutrophils.">Robust ligature-induced model of murine periodontitis for the evaluation of oral neutrophils.</a> Journal of Visualized Experiments. 2020 (155), 6-13 (2019).</li><li>Cheng, R., Wu, Z., Li, M., Shao, M., Hu, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interleukin-1&#946;+is+a+potential+therapeutic+target+for+periodontitis:+a+narrative+review.">Interleukin-1&#946; is a potential therapeutic target for periodontitis: a narrative review.</a> International Journal of Oral Science. 12 (1), 1-9 (2020).</li><li>Abe, T., Hajishengallis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+the+ligature-induced+periodontitis+model+in+mice.">Optimization of the ligature-induced periodontitis model in mice.</a> Journal of Immunological Methods. 394 (1-2), 49-54 (2013).</li><li>Jeong-Hyon, K., Bon-Hyuk, G., Sang-Soo, N., Yeon-Cheol, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+rat+models+of+periodontitis+treated+with+natural+extracts.">A review of rat models of periodontitis treated with natural extracts.</a> Journal of Traditional Chinese Medical Sciences. 7 (2), 95-103 (2020).</li><li>Marchesan, 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=An+experimental+murine+model+to+study+periodontitis.">An experimental murine model to study periodontitis.</a> Nature Protocols. 13 (10), 2247-2267 (2018).</li><li>Lin, P., 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=Application+of+ligature-induced+periodontitis+in+mice+to+explore+the+molecular+mechanism+of+periodontal+disease.">Application of ligature-induced periodontitis in mice to explore the molecular mechanism of periodontal disease.</a> International Journal of Molecular Sciences. 22 (16), 8900 (2021).</li><li>Irie, M. 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=Use+of+micro-computed+tomography+for+bone+evaluation+in+dentistry.">Use of micro-computed tomography for bone evaluation in dentistry.</a> Brazilian Dental Journal. 29 (3), 227-238 (2018).</li><li>Haas, L. F., Zimmermann, G. S., De Luca Canto, G., Flores-Mir, C., Corr&#234;a, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precision+of+cone+beam+CT+to+assess+periodontal+bone+defects:+a+systematic+review+and+meta-analysis.">Precision of cone beam CT to assess periodontal bone defects: a systematic review and meta-analysis.</a> Dentomaxillofacial Radiology. 47 (2), 20170084 (2018).</li><li>Kamburo&#287;lu, K., Ere&#351;, G., Akg&#252;n, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Qualitative+and+quantitative+assessment+of+alveolar+bone+destruction+in+adult+rats+using+CBCT.">Qualitative and quantitative assessment of alveolar bone destruction in adult rats using CBCT.</a> Journal of Veterinary Dentistry. 36 (4), 245-250 (2019).</li><li>Sousa Melo, S. L., Rovaris, K., Javaheri, A. M., de Rezen de Barbosa, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cone-beam+computed+tomography+(CBCT)+imaging+for+the+assessment+of+periodontal+disease.">Cone-beam computed tomography (CBCT) imaging for the assessment of periodontal disease.</a> Current Oral Health Reports. 7 (4), 376-380 (2020).</li></ol>

This method describes the induction of PD in rats following a combined technique of Pg-LPS injections and ligature placement around the M1, revealing that significant changes in the periodontal tissues and alveolar bone could be induced in 14 days following this method.
During this procedure, attention to different critical steps must be provided. During animal anesthesia and procedure preparation, assessing the proper anesthesia during the surgical process is critical for its success...

Periodontitis (PD) is the sixth most prevalent public health condition worldwide, affecting approximately 11% of the total population, being an advanced, irreversible, and destructive form of periodontal disease1,2. PD is an inflammatory process that affects the gingival and periodontal tissues, which results in gingiva recession, apical migration of the junctional epithelium with pocket development, and the loss of alveolar bone3. Furthermore, PD is associated with several systemic diseases, including cardiovascular disease, obesity, diabetes, and rheumatoid arthritis, for which environmental and host-specific factors play a significant role4,5.
Hence, PD is a multifactorial disease primarily initiated by the accumulation of microbial plaque - resulting from dysbiosis of microbial communities - and by an exaggerated host immune response to periodontal pathogens, which leads to the breakdown of periodontal tissue4,6. Among several periodontal bacteria, the gram-negative anaerobic bacterium Porphyromonas gingivalis is one of the key pathogens in PD4. P. gingivalis contains a complex lipopolysaccharide (LPS) in its walls, a molecule known to induce polymorphonuclear leukocyte infiltration and vascular dilatation in inflamed periodontal tissues7. This results in the production of inflammatory mediators, such as interleukin 1 (IL-1), IL-6, and IL-8, tumor necrosis factor (TNF), or prostaglandins, with a subsequent osteoclast activation and bone resorption, leading to tissue destruction and ultimate tooth loss3.
Among the different advantages of animal models include the capacity to mimic cellular complexities as in humans, or to be more accurate than in vitro studies, which are carried out on plastic surfaces with limited cell types8. For modeling PD experimentally in vivo, different animal species have been used, like non-human primates, dogs, pigs, ferrets, rabbits, mice, and rats9. However, rats are the most extensively studied animal model for the pathogenesis of PD because they are inexpensive and easy to handle10. Their dental gingival tissue has similar structural features to human gingival tissue, with a shallow gingival sulcus and junctional epithelium attached to the tooth surface. Furthermore, as in humans, the junctional epithelium facilitates the passage of bacterial, foreign materials, and exudates from inflammatory cells 9.
One of the most reported experimental models of PD induction in rats is the placement of ligatures around the teeth, which is technically challenging but reliable10. The ligature placement facilitates dental plaque and bacterial accumulation, generating a dysbiosis in the gingival sulci, that causes periodontal tissue inflammation and destruction11. Loss of periodontal attachment and resorption of alveolar bone could occur in 7 days in this rat model8.
Another animal model for PD consists of the injection of LPS into the gingival tissue. As a result, osteoclastogenesis and bone loss are stimulated. The histopathological features of this model are similar to human-established PD, characterized by higher levels of proinflammatory cytokines, collagen degradation, and alveolar bone resorption6,8.
Thus, the aim of this study was to describe a simple rat model of experimental PD based on the techniques of P. gingivalis-LPS (Pg-LPS) injections, combined with ligature placement around the first maxillary molars (M1). This is a model with similar characteristics to those observed in human PD disease, which could be used in the study of disease progression mechanisms and future possible treatments.

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		<tr>
			<td>Adsorbent paper point n&#186;30&#160;</td>
			<td>Proclinc</td>
			<td>8187</td>
			<td></td>
		</tr>
		<tr>
			<td>Aprotinin</td>
			<td>Sigma-Aldrich</td>
			<td>A1153</td>
			<td></td>
		</tr>
		<tr>
			<td>Atipamezole</td>
			<td>Dechra</td>
			<td>573751.5</td>
			<td>Revanzol 5 mg/mL</td>
		</tr>
		<tr>
			<td>Braided silk ligature (5/0)&#160;</td>
			<td>Laboratorio Arago Sl</td>
			<td>613112</td>
			<td></td>
		</tr>
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			<td>Buprenorphine&#160;</td>
			<td>Richter pharma</td>
			<td>578816.6</td>
			<td>Bupaq 0.3 mg/mL</td>
		</tr>
		<tr>
			<td>Cone-beam computed tomography (CBCT) Scanner&#160;</td>
			<td>MyRay</td>
			<td>hyperion X9</td>
			<td>Model Hyperion X9</td>
		</tr>
		<tr>
			<td>CTAn software</td>
			<td>SkyScan</td>
			<td></td>
			<td>Version 1.13.4.0</td>
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		<tr>
			<td>Dental explorer&#160;</td>
			<td>Proclinc</td>
			<td>99743</td>
			<td></td>
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			<td>Diamond lance-shaped bur&#160;</td>
			<td>Dentaltix</td>
			<td>IT21517</td>
			<td></td>
		</tr>
		<tr>
			<td>Food maintenance diet</td>
			<td>Sodispain research</td>
			<td>ROD14&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Heated surgical platform</td>
			<td>PetSavers</td>
			<td></td>
			<td></td>
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		<tr>
			<td>Hollenback carver</td>
			<td>Hu-FRIEDY&#160;</td>
			<td>HF45234</td>
			<td></td>
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			<td>Hypodermic needle&#160;&#160;</td>
			<td>BD&#160;</td>
			<td>300600</td>
			<td>25G X 5/8&#8221; - 0,5 X 16 MM</td>
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		<tr>
			<td>Isoflurane&#160;</td>
			<td>Karizoo</td>
			<td></td>
			<td>Isoflutek 1000mg/g</td>
		</tr>
		<tr>
			<td>Ketamine&#160;&#160;</td>
			<td>Dechra</td>
			<td>581140.6</td>
			<td>Anesketin 100 mg/mL</td>
		</tr>
		<tr>
			<td>Lipopolysaccharide&#160; derived from P.Gingivalis&#160;</td>
			<td>InvivoGen</td>
			<td>TLRL-PGLPS</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Fisher Scientific</td>
			<td>M/4000/PB08</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro needle holter</td>
			<td>Fehling Surgical Instruments</td>
			<td>KOT-6</td>
			<td></td>
		</tr>
		<tr>
			<td>Microsurgical pliers</td>
			<td>KLS Martin</td>
			<td>12-384-06-07</td>
			<td></td>
		</tr>
		<tr>
			<td>microsurgical scissors&#160;</td>
			<td>S&#38;T microsurgical instruments</td>
			<td>SDC-15 RV</td>
			<td></td>
		</tr>
		<tr>
			<td>Monitor iMEC 8 Vet</td>
			<td>Mindray&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Multiplex bead immunoassay</td>
			<td>Procartaplex, Thermo fisher Scientific</td>
			<td>PPX-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde (PFA)&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>8187151000</td>
			<td></td>
		</tr>
		<tr>
			<td>Periosteal microsurgical elevator&#160;</td>
			<td>Dentaltix</td>
			<td>CU19112468</td>
			<td></td>
		</tr>
		<tr>
			<td>Phenylmethylsulfonylfluoride (PMSF)&#160;</td>
			<td>Roche</td>
			<td>10837091001</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate Buffer Solution (PBS)</td>
			<td>Capricorn Scientific</td>
			<td>PBS-1A</td>
			<td></td>
		</tr>
		<tr>
			<td>PhosSTOP&#160;</td>
			<td>Roche</td>
			<td>4906845001</td>
			<td>Commercial phosphatase inhibitor tablet&#160;</td>
		</tr>
		<tr>
			<td>Plastic vial</td>
			<td>SPL Lifesciencies</td>
			<td>60015</td>
			<td>1.5mL</td>
		</tr>
		<tr>
			<td>Saline</td>
			<td>Cinfa</td>
			<td>204024.3</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo Microscope&#160;</td>
			<td>Zeiss</td>
			<td></td>
			<td>Model SteREO Discovery.V12</td>
		</tr>
		<tr>
			<td>Surgical loupes led light</td>
			<td>Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical scissors&#160;</td>
			<td>Zepf Surgical</td>
			<td>08-1701-17</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe&#160;</td>
			<td>BD plastipak</td>
			<td>303172</td>
			<td>1mL</td>
		</tr>
		<tr>
			<td>Veterinary dental micromotor</td>
			<td>Eickemeyer</td>
			<td>174028</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Calier</td>
			<td>20102-003</td>
			<td>Xilagesic 20 mg/mL</td>
		</tr>
	</tbody>
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induction of periodontitis via a combination of ligature and lipopolysaccharide injection in a rat model

Periodontitis (PD) is a highly prevalent, chronic immune-inflammatory disease of the periodontium, that results in a loss of gingival soft tissue, periodontal ligament, cementum, and alveolar bone. In this study, a simple method of PD induction in rats is described. We provide detailed instructions for placement of the ligature model around the first maxillary molars (M1) and a combination of injections of lipopolysaccharide (LPS), derived from Porphyromonas gingivalis at the mesio-palatal side of the M1. The induction of periodontitis was maintained for 14 days, promoting the accumulation of bacteria biofilm and inflammation. To validate the animal model, IL-1&#946;, a key inflammatory mediator, was determined by an immunoassay in the gingival crevicular fluid (GCF), and alveolar bone loss was calculated using cone beam computed tomography (CBCT). This technique was effective in promoting gingiva recession, alveolar bone loss, and an increase in IL-1&#946; levels in the GCF at the end of the experimental procedure after 14 days. This method was effective in inducing PD, thus being able to be used in studies on disease progression mechanisms and future possible treatments.

A timeline of the experimental steps is presented in Figure 1. Figure 2A shows an image of the mandibula after surgical intervention, with ligature placement around the sulcus of the M1 at time 0 of the experiment. Figure 2B shows how, after 14 days of the procedure, the ligature around the M1 enters the gingival sulcus, causing inflammation of the gingiva and infiltrating accumulation.
<p class="jove_content biglegend" fo:keep-...

Watch this Scientific Journal Video about Induction of Periodontitis via a Combination of Ligature and Lipopolysaccharide Injection in a Rat Model at JoVE.com

Induction of Periodontitis via a Combination of Ligature and Lipopolysaccharide Injection in a Rat Model

In this study, a rat model of induction of periodontitis is presented via a combination of retentive ligature and repetitive injections of lipopolysaccharide derived from Porphyromonas gingivalis, over 14 days around the first maxillary molars. The ligation and LPS injection techniques were effective in inducing peridontitis, resulting in alveolar bone loss and inflammation.

Induction of Periodontitis via a Combination of Ligature and Lipopolysaccharide Injection in a Rat Model

Periodontitis (PD) is a highly prevalent, chronic immune-inflammatory disease of the periodontium, that results in a loss of gingival soft tissue, ...

This is a rat model of experimental periodontitis, based on the techniques of lipopolysaccharide injections combined with ligature placement, offering an effective method to study disease progression and to evaluate treatments for periodontitis. Combining both techniques with individual methods culminates in a rapid disease induction, amplifying destructive inflammatory response and increasing loss of connective tissue and alveolar bone resorption. This method provides a valuable opportunity to assess the impact of periodontitis treatments.Demonstrating the procedure will be Dr.Oscar Villa, PhD. Begin by sterilizing all surgical instruments before surgery. Prepare a mix of ketamine and xylazine by mixing 1.6 milliliters of ketamine with one milliliter of xylazine, diluted in PBS or saline, and store the stock at four degrees Celsius.Dilute atipamezole to a final concentration of 0.25 milligrams per milliliter and buprenorphine to a final concentration of 0.03 milligrams per milliliter in PBS or saline, and store the stocks at four degrees Celsius. Prepare one milliliter of PG-LPS in sterile saline and store the stock at minus 20 degrees Celsius. Use female and male Wistar rats for the experiment.Keep the animals housed in groups under the appropriate environment, with food and standard water offered ad libitum. After the rat is anesthetized, place the animal on its back on a heated surgical platform. Cover the animal's body during the procedure to prevent heat loss.Administer 100%oxygen using a small nose cone, and monitor the pulse rate and oxygen saturation by pulse oximetry. Now, open the rat mouth using an aluminum mouth gag around the incisors. Retract the tongue with it and stabilize the maxilla and mandible in an open, comfortable working position, enabling access to mandibular molars.Collect GCF using a total of four absorbent paper point number 30, by inserting it into the gingival crevice around the mesiopalatal of the M1 until slight resistance. Retain the paper point in the same position for 30 seconds before immediate removal. After collection, transfer the paper point immediately into a plastic vial and store at minus 80 degrees Celsius until assay performance.Position the distal tail of the suture on the palatal side of the dentition and insert the proximal segment between the contact of M1 and second maxillary molars. Use the periosteal microsurgical elevator to insert the suture within the sulcus. Wrap the ligature around the buccal surface of the M1 very carefully, as the tissues at this level present a narrow zone of attached gingiva.Ensure the suture is tightened on both ends to be driven into the gingival sulcus. Next, tie the ends of the suture with a surgeon's knot and trim the tails as short as possible. Insert the knot in the sulcus.After ligature positioning, inject 40 microliters of PG-LPS in sterile saline into the subgingival tissue at the mesiopalatal side of the M1 bilaterally. To examine and adjust the ligature, place the anesthetized animal on its back and use a small nose cone during the procedure with 1%isoflurane and 100%oxygen for maintenance of the animal anesthesia. Open the wrap mouth using the aluminum mouth gag around the incisors, retracting the tongue with it and stabilizing the maxilla and mandible in an open, comfortable working position, enabling access to ligatures.Tighten the ligatures against the gingiva with the help of a periosteal microsurgical elevator and make sure the suture of the ligatures is inserted, creating inflammation around the gingiva. After the ligature adjustment, bilaterally inject 40 microliters of PG-LPS into the subgingival tissue at the mesiopalatal side of the M1, as demonstrated earlier. After sacrificing the animal on the 14th day, collect GCF as shown earlier.Transfer the paper point immediately into a plastic vial and store at minus 80 degrees Celsius until assay performance. The bi-dimensional images of the alveolar bone of maxillary molars show more bone volume in the basal control and higher alveolar bone loss after establishing periodontitis. Analysis of the sagittal images highlights a more significant alveolar bone loss in the interradicular bone area of the M1 and M2 after periodontitis establishment, compared to the basal control group.After sacrifice, the palate presented differences in gingival recession in the M1 among different groups. The periodontitis group shows a more remarkable apical gingival migration and inflammation of the gingiva around the maxillary molars compared to the basal control group. Also, the periodontitis group showed a significantly higher release of pro-inflammatory cytokine 1L-1 beta from GCF than the control group.Crucial steps in the procedure are the correct placement of the suture and knot in the sulcus, proper adjustment of the ligature, and accurate lipopolysaccharide injection during the 14-day protocol.

induction-periodontitis-via-combination-ligature-lipopolysaccharide

Research

JoVE Journal

Immunology and Infection

Preparation of Mouse Pituitary Immunogen for the Induction of Experimental Autoimmune Hypophysitis

Autoimmune hypophysitis is a chronic inflammation of the pituitary gland caused or accompanied by autoimmunity1. It has traditionally been considered a rare disease but reporting has increased markedly in recent years. Hypophysitis, in fact, develops not uncommonly as a "side effect" in cancer patients treated with antibodies that block inhibitory receptors expressed on T lymphocytes, such as CTLA-42 and PD-1 receptors. Autoimmune hypophysitis can be induced experimentally by injecting mice with pituitary proteins mixed with an adjuvant3. In this video article we demonstrate how to extract proteins from mouse pituitary glands and how to prepare them in a form suitable for inducing autoimmune hypophysitis in SJL mice.

Autoimmune hypophysitis can be reproduced in mice by injecting an extract of mouse pituitary proteins.

Autoimmune hypophysitis is a chronic inflammation of the pituitary gland caused or accompanied by autoimmunity1.  It has traditionally been considered a ...

Induction of Experimental Autoimmune Hypophysitis in SJL Mice

Autoimmune hypophysitis can be reproduced experimentally by the injection of pituitary proteins mixed with an adjuvant into susceptible mice1. Mouse models allow us to study how diseases unfold, often providing a good replica of the same processes occurring in humans. For some autoimmune diseases, like type 1A diabetes, there are models (the NOD mouse) that spontaneously develop a disease similar to the human counterpart. For many other autoimmune diseases, however, the model needs to be induced experimentally. A common approach in this regard is to inject the mouse with a dominant antigen derived from the organ being studied. For example, investigators interested in autoimmune thyroiditis inject mice with thyroglobulin2, and those interested in myasthenia gravis inject them with the acetylcholine receptor3. If the autoantigen for a particular autoimmune disease is not known, investigators inject a crude protein extract from the organ targeted by the autoimmune reaction. For autoimmune hypophysitis, the pathogenic autoantigen(s) remain to be identified4, and thus a crude pituitary protein preparation is used. In this video article we demonstrate how to induce experimental autoimmune hypophysitis in SJL mice.

This video shows how to induce autoimmune hypophysitis in SJL mice and how to assess its severity by histopathology.

Autoimmune hypophysitis can be reproduced experimentally by the injection of pituitary proteins mixed with an adjuvant into susceptible mice1. Mouse ...

Induction of Graft-versus-host Disease and In Vivo T Cell Monitoring Using an MHC-matched Murine Model

Graft-versus-host disease (GVHD) is the limiting barrier to the broad use of bone marrow transplant as a curative therapy for a variety of hematological deficiencies. GVHD is caused by mature alloreactive T cells present in the bone marrow graft that are infused into the recipient and cause damage to host organs. However, in mice, T cells must be added to the bone marrow inoculum to cause GVHD. Although extensive work has been done to characterize T cell responses post transplant, bioluminescent imaging technology is a non-invasive method to monitor T cell trafficking patterns in vivo. 
Following lethal irradiation, recipient mice are transplanted with bone marrow cells and splenocytes from donor mice. T cell subsets from L2G85.B6 (transgenic mice that constitutively express luciferase) are included in the transplant. By only transplanting certain T cell subsets, one is able to track specific T cell subsets in vivo, and based on their location, develop hypotheses regarding the role of specific T cell subsets in promoting GVHD at various time points. At predetermined intervals post transplant, recipient mice are imaged using a Xenogen IVIS CCD camera. Light intensity can be quantified using Living Image software to generate a pseudo-color image based on photon intensity (red = high intensity, violet = low intensity). 
Between 4-7 days post transplant, recipient mice begin to show clinical signs of GVHD. Cooke et al.1 developed a scoring system to quantitate disease progression based on the recipient mice fur texture, skin integrity, activity, weight loss, and posture. Mice are scored daily, and euthanized when they become moribund. Recipient mice generally become moribund 20-30 days post transplant. 
Murine models are valuable tools for studying the immunology of GVHD. Selectively transplanting particular T cell subsets allows for careful identification of the roles each subset plays. Non-invasively tracking T cell responses in vivo adds another layer of value to murine GVHD models.

Induction of Graft-versus-host Disease and In Vivo T Cell Monitoring Using an MHC-matched Murine Model

Murine bone marrow transplantation is a widely used technique to study immunological mechanisms governing graft-versus-host disease in humans. The ability to monitor T cell trafficking patterns in vivo allows for detailed analysis of the development and perpetuation of T cell responses during graft-versus-host disease.

Graft-versus-host disease (GVHD) is the limiting barrier to the broad use of bone marrow transplant as a curative therapy for a variety of hematological ...

A Method for Generating Pulmonary Neutrophilia Using Aerosolized Lipopolysaccharide

Acute lung injury (ALI) is a severe disease characterized by alveolar neutrophilia, with limited treatment options and high mortality. Experimental models of ALI are key in enhancing our understanding of disease pathogenesis. Lipopolysaccharide (LPS) derived from gram positive bacteria induces neutrophilic inflammation in the airways and lung parenchyma of mice. Efficient pulmonary delivery of compounds such as LPS is, however, difficult to achieve. In the approach described here, pulmonary delivery in mice is achieved by challenge to aerosolized Pseudomonas aeruginosa LPS. Dissolved LPS was aerosolized by a nebulizer connected to compressed air. Mice were exposed to a continuous flow of LPS aerosol in a Plexiglas box for 10 min, followed by 2 min conditioning after the aerosol was discontinued. Tracheal intubation and subsequent bronchoalveolar lavage, followed by formalin perfusion was next performed, which allows for characterization of the sterile pulmonary inflammation. Aerosolized LPS generates a pulmonary inflammation characterized by alveolar neutrophilia, detected in bronchoalveolar lavage and by histological assessment. This technique can be set up at a small cost with few appliances, and requires minimal training and expertise. The exposure system can thus be routinely performed at any laboratory, with the potential to enhance our understanding of lung pathology.

We describe a method for inducing neutrophilic pulmonary inflammation by challenge to aerosolized lipopolysaccharide by nebulization, to model acute lung injury. In addition, basic surgical techniques for lung isolation, tracheal intubation and bronchoalveolar lavage are also described.

Acute lung injury (ALI) is a severe disease characterized by alveolar neutrophilia, with limited treatment options and high mortality. Experimental models ...

Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat

Investigation of the interactions between animal host and bacterial pathogen is only meaningful if the infection model employed replicates the principal features of the natural infection. This protocol describes procedures for the establishment and evaluation of systemic infection due to neuropathogenic Escherichia coli K1 in the neonatal rat. Colonization of the gastrointestinal tract leads to dissemination of the pathogen along the gut-lymph-blood-brain course of infection and the model displays strong age dependency. A strain of E. coli O18:K1 with enhanced virulence for the neonatal rat produces exceptionally high rates of colonization, translocation to the blood compartment and invasion of the meninges following transit through the choroid plexus. As in the human host, penetration of the central nervous system is accompanied by local inflammation and an invariably lethal outcome. The model is of proven utility for studies of the mechanism of pathogenesis, for evaluation of therapeutic interventions and for assessment of bacterial virulence.

Non-Invasive Model of Neuropathogenic Escherichia coli Infection in the Neonatal Rat

Here, a procedure is described for the establishment of systemic infection in the neonatal rat with cultures of Escherichia coli K1. This non-invasive procedure permits colonization of the gastrointestinal tract, translocation of the pathogen to the systemic circulation, and invasion of the central nervous system at the choroid plexus.

Investigation of the interactions between animal host and bacterial pathogen is only meaningful if the infection model employed replicates the principal ...

Induction of Paralysis and Visual System Injury in Mice by T Cells Specific for Neuromyelitis Optica Autoantigen Aquaporin-4

While it is recognized that aquaporin-4 (AQP4)-specific T cells and antibodies participate in the pathogenesis of neuromyelitis optica (NMO), a human central nervous system (CNS) autoimmune demyelinating disease, creation of an AQP4-targeted model with both clinical and histologic manifestations of CNS autoimmunity has proven challenging. Immunization of wild-type (WT) mice with AQP4 peptides elicited T cell proliferation, although those T cells could not transfer disease to na&#239;ve recipient mice. Recently, two novel AQP4 T cell epitopes, peptide (p) 135-153 and p201-220, were identified when studying immune responses to AQP4 in AQP4-deficient (AQP4-/-) mice, suggesting T cell reactivity to these epitopes is normally controlled by thymic negative selection. AQP4-/- Th17 polarized T cells primed to either p135-153 or p201-220 induced paralysis in recipient WT mice, that was associated with predominantly leptomeningeal inflammation of the spinal cord and optic nerves. Inflammation surrounding optic nerves and involvement of the inner retinal layers (IRL) were manifested by changes in serial optical coherence tomography (OCT). Here, we illustrate the approaches used to create this new in vivo model of AQP4-targeted CNS autoimmunity (ATCA), which can now be employed to study mechanisms that permit development of pathogenic AQP4-specific T cells and how they may cooperate with B cells in NMO pathogenesis.

Here, we present a protocol to induce paralysis and opticospinal inflammation by transfer of aquaporin-4 (AQP4)-specific T cells from AQP4-/- mice into WT mice. In addition, we demonstrate how to use serial optical coherence tomography to monitor visual system dysfunction.

While it is recognized that aquaporin-4 (AQP4)-specific T cells and antibodies participate in the pathogenesis of neuromyelitis optica (NMO), a human ...

Two-photon Intravital Imaging of Leukocytes During the Immune Response in Lipopolysaccharide-treated Mouse Liver

Sepsis is a type of severe infection that can cause organ failure and tissue damage. Although the mortality and morbidity rates associated with sepsis are extremely high, no direct treatment or organ-related mechanism has been examined in detail in real time. The liver is the key organ that manages toxins and infections in the human body. Herein, we aimed to perform intravital imaging of mouse liver after induction of endotoxemia in order to track the motility of immune cells, such as neutrophils and liver capsular macrophages (LCMs). Accordingly, we designed a novel surgical method for exposure of the liver with minimally invasive surgery. Mice were intraperitoneally injected with lipopolysaccharide (LPS), a common endotoxin. Using our novel surgical approach for exposure and intravital imaging of the mouse liver, we found that neutrophil recruitment in LPS-treated LysM-green fluorescent protein (GFP) mouse liver was increased compared with that in phosphate-buffered saline-treated liver. After LPS treatment, the number of neutrophils increased significantly with time. Additionally, using CX3Cr1-GFP mice, we successfully visualized liver resident macrophages called LCMs. Therefore, to investigate the efficacy of new reagents to control immune mobility in vivo, determining the motility and morphology of neutrophils and LCMs in the liver may allow us to identify therapeutic effect in organ failure and tissue damage caused by leukocytes activation in sepsis.

We established a novel surgical protocol for two-photon imaging of live mice liver with minimal invasion. With this technique, we identified the detailed structure of the liver during lipopolysaccharide-induced endotoxemia. We anticipate that this method may be utilized to determine the effectiveness of various reagents treatment to hepatic leukocyte migration.

Sepsis is a type of severe infection that can cause organ failure and tissue damage. Although the mortality and morbidity rates associated with sepsis are ...

Deep Dermal Injection As a Model of Candida albicans Skin Infection for Histological Analyses

The skin is an extremely extended organ of the body and, due to this large surface, it is continuously exposed to microorganisms. Skin damage can easily lead to infections in the dermis which can, in turn, result in the dissemination of pathogens into the bloodstream. Understanding how the immune system fights infections at the very early stage and how the host can eliminate the pathogens is an important step to set the base for future therapeutic interventions. Here we describe a model of Candida albicans infection that can visualize the processes that occur early during an infection, including when the pathogen has passed the epithelial barrier, as well as the immune response elicited by the C. albicans invasion. We used this infection model to perform histological analyses that show the immune cells that infiltrate the skin as well as the presence and localization of the pathogen. Samples collected after the infection can be processed for RNA extraction.

Deep Dermal Injection As a Model of Candida albicans Skin Infection for Histological Analyses

Here we describe a protocol that allows histological and molecular analysis of skin samples after Candida albicans intradermal injection. This protocol maintains the structural integrity of the skin and allows for the localization of tissue-resident or newly recruited immune cells as well as the pathogen distribution.

The skin is an extremely extended organ of the body and, due to this large surface, it is continuously exposed to microorganisms. Skin damage can easily ...

Induction of Mouse Lung Injury by Endotracheal Injection of Bleomycin

Pulmonary fibrosis is a hallmark of several human lung diseases with a different etiology. Since current therapies are rather limited, mouse models continue to be an essential tool for developing new antifibrotic strategies. Here we provide an effective method to investigate in vivo antifibrotic activity of human mesenchymal stromal cells obtained from whole umbilical cord (hUC-MSC) in attenuating bleomycin-induced lung injury. C57BL/6 mice receive a single endotracheal injection of bleomycin (1.5 U/kg body weight) followed by a double infusion of hUC-MSC (2.5 x 105) into the tail vein, 24 h and 7 days after the bleomycin administration. Upon sacrifice at days 8, 14, or 21, inflammatory and fibrotic changes, collagen content, and hUC-MSC presence in explanted lung tissue are analyzed. The injection of bleomycin into the mouse&#160;trachea allows the direct targeting of the lungs, leading to extensive pulmonary inflammation and fibrosis. The systemic administration of a double dose of hUC-MSC results in the early blunting of the bleomycin-induced lung injury. Intravenously infused hUC-MSC are transiently engrafted into the mouse lungs, where they exert their anti-inflammatory and antifibrotic activity. In conclusion, this protocol has been successfully applied for the preclinical testing of hUC-MSC in an experimental mouse model of human pulmonary fibrosis. However, this technique can be easily extended both to study the effect of different endotracheally administered substances on the pathophysiology of the lungs and to validate new anti-inflammatory and antifibrotic systemic therapies.

Here we present an effective method to investigate the antifibrotic activity of intravenously infused human mesenchymal stromal cells obtained from the whole umbilical cord following the induction of lung injury by an endotracheal injection of bleomycin in C57BL/6 mice. This protocol can be easily extended to the preclinical testing of other therapeutics.

Pulmonary fibrosis is a hallmark of several human lung diseases with a different etiology. Since current therapies are rather limited, mouse models ...

Induction and Scoring of Graft-Versus-Host Disease in a Xenogeneic Murine Model and Quantification of Human T Cells in Mouse Tissues using Digital PCR

Acute graft-versus-host disease (GVHD) is a significant limitation for patients receiving hematopoietic stem cell transplant as therapy for hematological deficiencies and malignancies. Acute GVHD occurs when donor T cells recognize host tissues as a foreign antigen and mount an immune response to the host. Current treatments involve toxic immunosuppressive drugs that render patients susceptible to infection and recurrence. Thus, there is ongoing research to provide an acute GVHD therapy that can effectively target donor T cells and reduce side effects. Much of this pre-clinical work uses the xenogenic GVHD (xenoGVHD) murine model that allows for testing of immunosuppressive therapies on human cells rather than murine cells in an in vivo system. This protocol outlines how to induce xenoGVHD and how to blind and standardize clinical scoring to ensure consistent results. Additionally, this protocol describes how to use digital PCR to detect human T cells in mouse tissues, which can subsequently be used to quantify efficacy of tested therapies. The xenoGVHD model not only provides a model to test GVHD therapies but any therapy that can suppress human T cells, which could then be applied to many inflammatory diseases.

Here, we present a protocol to induce and score disease in a xenogeneic graft-versus-host disease (xenoGVHD) model. xenoGVHD provides an in vivo model to study immunosuppression of human T cells. Additionally, we describe how to detect human T cells in tissues with digital PCR as a tool to quantify immunosuppression.

Acute graft-versus-host disease (GVHD) is a significant limitation for patients receiving hematopoietic stem cell transplant as therapy for hematological ...