The authors thank Peter Bollen, head of the Biomedical Laboratory for lending the equipment needed to record the footage seen through the microscopes.

Animals were housed in the University of Southern Denmark Animal Care Facility as per institutional guidelines. All procedures involving animal subjects have been approved by The Animal Experiments Inspectorate, Ministry of Environment and Food of Denmark.
1. Pre-surgery irradiation
NOTE: Pre-surgery irradiation takes place 7 days before surgery.
<ol>
	<li>Induce anesthesia.
	<ol>
		<li>Place the mouse in an induction box and set the vaporizer to 3% isoflurane wit...

<ol>
	<li>Lawenda, B. D., Mondry, T. E., Johnstone, P. A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphedema:+a+primer+on+the+identification+and+management+of+a+chronic+condition+in+oncologic+treatment.">Lymphedema: a primer on the identification and management of a chronic condition in oncologic treatment.</a> CA: A Cancer Journal for Clinicians. 59 (1), 8-24 (2009).</li><li>Greene, A. K., Greene, A. K., Slavin, S. A., Brorson, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiology+and+morbidity+of+lymphedema.">Epidemiology and morbidity of lymphedema.</a> Lymphedema: Presentation, Diagnosis, and Treatment. , 33-44 (2015).</li><li>Hespe, G. E., Nores, G. G., Huang, J. J., Mehrara, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathophysiology+of+lymphedema-Is+there+a+chance+for+medication+treatment?.">Pathophysiology of lymphedema-Is there a chance for medication treatment?.</a> Journal of Surgical Oncology. 115 (1), 96-98 (2017).</li><li>Grada, A. A., Phillips, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphedema:+Pathophysiology+and+clinical+manifestations.">Lymphedema: Pathophysiology and clinical manifestations.</a> Journal of the American Academy of Dermatology. 77 (6), 1009-1020 (2017).</li><li>Chang, D. W., Masia, J., Garza, R., Skoracki, R., Neligan, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphedema:+Surgical+and+Medical+Therapy.">Lymphedema: Surgical and Medical Therapy.</a> Plastic and Reconstructive Surgery. 138 (3 Suppl), 209S-218S (2016).</li><li>Carl, H. 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=Systematic+Review+of+the+Surgical+Treatment+of+Extremity+Lymphedema.">Systematic Review of the Surgical Treatment of Extremity Lymphedema.</a> Journal of Reconstructive Microsurgery. 33 (6), 412-425 (2017).</li><li>DiSipio, T., Rye, S., Newman, B., Hayes, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incidence+of+unilateral+arm+lymphoedema+after+breast+cancer:+a+systematic+review+and+meta-analysis.">Incidence of unilateral arm lymphoedema after breast cancer: a systematic review and meta-analysis.</a> The Lancet Oncology. 14 (6), 500-515 (2013).</li><li>Douglass, J., Graves, P., Gordon, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-Care+for+Management+of+Secondary+Lymphedema:+A+Systematic+Review.">Self-Care for Management of Secondary Lymphedema: A Systematic Review.</a> PLoS Neglected Tropical Diseases. 10 (6), e0004740 (2016).</li><li>Shih, Y. C. 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=Incidence,+treatment+costs,+and+complications+of+lymphedema+after+breast+cancer+among+women+of+working+age:+a+2-year+follow-up+study.">Incidence, treatment costs, and complications of lymphedema after breast cancer among women of working age: a 2-year follow-up study.</a> Journal of Clinical Oncology. 27 (12), 2007-2014 (2009).</li><li>Ridner, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+psycho-social+impact+of+lymphedema.">The psycho-social impact of lymphedema.</a> Lymphatic Research and Biology. 7 (2), 109-112 (2009).</li><li>Gutknecht, 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=Cost-of-illness+of+patients+with+lymphoedema.">Cost-of-illness of patients with lymphoedema.</a> Journal of the European Academy of Dermatology and Venereology. 31 (11), 1930-1935 (2017).</li><li>Hayes, 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=Prevalence+and+prognostic+significance+of+secondary+lymphedema+following+breast+cancer.">Prevalence and prognostic significance of secondary lymphedema following breast cancer.</a> Lymphatic Research and Biology. 9 (3), 135-141 (2011).</li><li>Danese, C. A., Georgalas-Bertakis, M., Morales, L. E. <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+chronic+postsurgical+lymphedema+in+dogs'+limbs.">A model of chronic postsurgical lymphedema in dogs' limbs.</a> Surgery. 64 (4), 814-820 (1968).</li><li>Das, S. K., Franklin, J. D., O'Brien, B. M., Morrison, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+model+of+secondary+lymphedema+in+dogs.">A practical model of secondary lymphedema in dogs.</a> Plastic and Reconstructive Surgery. 68 (3), 422-428 (1981).</li><li>Huang, G. K., Hsin, Y. P. <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+model+for+lymphedema+in+rabbit+ear.">An experimental model for lymphedema in rabbit ear.</a> Microsurgery. 4 (4), 236-242 (1983).</li><li>Tobbia, 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=Lymphedema+development+and+lymphatic+function+following+lymph+node+excision+in+sheep.">Lymphedema development and lymphatic function following lymph node excision in sheep.</a> Journal of Vascular Research. 46 (5), 426-434 (2009).</li><li>Lahteenvuo, 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=Growth+factor+therapy+and+autologous+lymph+node+transfer+in+lymphedema.">Growth factor therapy and autologous lymph node transfer in lymphedema.</a> Circulation. 123 (6), 613-620 (2011).</li><li>Honkonen, K. 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=Lymph+node+transfer+and+perinodal+lymphatic+growth+factor+treatment+for+lymphedema.">Lymph node transfer and perinodal lymphatic growth factor treatment for lymphedema.</a> Annals of Surgery. 257 (5), 961-967 (2013).</li><li>Wang, G. Y., Zhong, S. Z. <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+experimental+lymphedema+in+rats'+limbs.">A model of experimental lymphedema in rats' limbs.</a> Microsurgery. 6 (4), 204-210 (1985).</li><li>Oashi, K., 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+new+model+of+acquired+lymphedema+in+the+mouse+hind+limb:+a+preliminary+report.">A new model of acquired lymphedema in the mouse hind limb: a preliminary report.</a> Annals of Plastic Surgery. 69 (5), 565-568 (2012).</li><li>Slavin, S. A., Van den Abbeele, A. D., Losken, A., Swartz, M. A., Jain, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Return+of+lymphatic+function+after+flap+transfer+for+acute+lymphedema.">Return of lymphatic function after flap transfer for acute lymphedema.</a> Annals of Surgery. 229 (3), 421-427 (1999).</li><li>Cheung, 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=An+experimental+model+for+the+study+of+lymphedema+and+its+response+to+therapeutic+lymphangiogenesis.">An experimental model for the study of lymphedema and its response to therapeutic lymphangiogenesis.</a> BioDrugs : Clinical Immunotherapeutics, Biopharmaceuticals and Gene Therapy. 20 (6), 363-370 (2006).</li><li>Rutkowski, J. M., Moya, M., Johannes, J., Goldman, J., Swartz, 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=Secondary+lymphedema+in+the+mouse+tail:+Lymphatic+hyperplasia,+VEGF-C+upregulation,+and+the+protective+role+of+MMP-9.">Secondary lymphedema in the mouse tail: Lymphatic hyperplasia, VEGF-C upregulation, and the protective role of MMP-9.</a> Microvascular Research. 72 (3), 161-171 (2006).</li><li>Tammela, 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=Therapeutic+differentiation+and+maturation+of+lymphatic+vessels+after+lymph+node+dissection+and+transplantation.">Therapeutic differentiation and maturation of lymphatic vessels after lymph node dissection and transplantation.</a> Nature Medicine. 13 (12), 1458-1466 (2007).</li><li>Frueh, F. 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=Animal+models+in+surgical+lymphedema+research--a+systematic+review.">Animal models in surgical lymphedema research--a systematic review.</a> Journal of Surgical Research. 200 (1), 208-220 (2016).</li><li>Jorgensen, M. G., 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=Quantification+of+Chronic+Lymphedema+in+a+Revised+Mouse+Model.">Quantification of Chronic Lymphedema in a Revised Mouse Model.</a> Annals of Plastic Surgery. 81 (5), 594-603 (2018).</li><li>Frueh, F. 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=High-resolution+3D+volumetry+versus+conventional+measuring+techniques+for+the+assessment+of+experimental+lymphedema+in+the+mouse+hindlimb.">High-resolution 3D volumetry versus conventional measuring techniques for the assessment of experimental lymphedema in the mouse hindlimb.</a> Scientific Reports. 6, 34673 (2016).</li><li>Biau, D. J., Kerneis, S., Porcher, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Statistics+in+brief:+the+importance+of+sample+size+in+the+planning+and+interpretation+of+medical+research.">Statistics in brief: the importance of sample size in the planning and interpretation of medical research.</a> Clinical Orthopaedics and Related Research. 466 (9), 2282-2288 (2008).</li><li>Korula, P., Varma, S. K., Sunderrao, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+wound+contraction+by+point-to-point+adherent+splintage.">Inhibition of wound contraction by point-to-point adherent splintage.</a> Plastic and Reconstructive Surgery. 95 (4), 725-730 (1995).</li><li>Komatsu, 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=Lymph+Drainage+During+Wound+Healing+in+a+Hindlimb+Lymphedema+Mouse+Model.">Lymph Drainage During Wound Healing in a Hindlimb Lymphedema Mouse Model.</a> Lymphatic Research and Biology. 15 (1), 32-38 (2017).</li></ol>

There are a few critical steps in this protocol. Firstly, it is important that the researchers take safety precautions when working with radioactivity. Secondly, during the surgical part of this protocol, it is important to start the procedure once the mouse has been anesthetized and finish it without unnecessary breaks. This is important to avoid an excessively long surgical period for the animal and to prevent that the anesthesia loses effect during surgery. It is recommended to only administer one bolus injection of a...

Lymphedema is characterized by an accumulation of lymph fluid that leads to localized tissue swelling, which mainly occurs due to impaired or disrupted flow of lymph fluid in the lymphatic vessels1. The lymph flow can be impaired or disrupted by infection, obstruction, injury or congenital defects in the lymphatic system2. These etiologies result in accumulation of lymphatic fluid, which leads to a chronic state of inflammation, resulting in subsequent fibrosis, as well as deposition of adipose tissue3. Lymphedema can be categorized as primary or secondary lymphedema. Primary lymphedema is caused by developmental abnormalities or genetic mutation2,4. Secondary lymphedema occurs due to underlying systemic disease, surgery or trauma2,4. Secondary lymphedema is the most common form of lymphedema in the world2. In developed countries, the most common cause of secondary lymphedema is oncological therapy such as adjuvant radiotherapy and lymph node dissection5. Lymphedema is most frequent among breast cancer patients, but can also develop in patients with gynecologic, melanoma, genitourinary or neck cancer6. It has been suggested that out of all women diagnosed with breast cancer, 21% will develop lymphedema7.
Lymphedema can be stressful to the patient both physically and psychologically. Patients with lymphedema have an increased risk of infection5,8,9, poor quality of life and can develop social anxiety and symptoms of depression10. The complications of chronic lymphedema lead to high cost of care and an increased disease burden9,11. Findings have also suggested that lymphedema might be associated with increased risk of death after breast cancer treatment12. Conservative management such as compression of the affected area, manual lymph drainage and general skincare remain the first line approach. There is currently no curative treatment6. Although progress has been made in the field of surgical and medical therapy, there is still room for improvement. More research, providing insight in the pathophysiology and progression of the disease, is needed to enable clinicians to provide better treatment options for the patients5.
Animal models are being used in preclinical research to understand the pathophysiology of diseases and develop potential treatment options. Several different lymphedema animal models have been established in canines13,14, rabbits15, sheep16, pigs17,18 and rodents19,20,21,22,23,24. The rodent model seems to be the most cost-effective model, when investigating the reconstruction of lymphatic function, due to rodents being easily accessible and relatively low-priced25. The majority of the mice models have focused on inducing lymphedema in the tail of the mice21,22,23. The tail model is very reliable but the exact surgical technique for inducing lymphedema varies significantly in previous published material. This results in fluctuations in duration and robustness of the developed lymphedema presented in known litterature25. Different techniques are also being used for inducing lymphedema in the hindlimb model and they also yield varying results, but the hindlimb model might be easier to understand from a translational perspective. Previous lymphedema models have been hampered by spontaneous lymphedema resolution and therefore a reproducible and permanent lymphedema model is needed25. Researchers have previously tried to increase the dose of radiation, to prevent the spontaneous lymphedema resolution, but this has often led to subsequent severe morbidity25.
This model results in statistically significant lymphedema, without causing severe morbidity, by combining microsurgery with radiation. The model has been revised from a previous surgical model by adding a dose of irradiation that induces lymphedema, without causing severe morbidity26. It also offers a great opportunity for microsurgical training. Having access to microsurgical equipment and a microscope is necessary, due to the small anatomical structures of the mice. The surgical procedure can be performed when the user has been taught basic microsurgical techniques, such as suturing with microsurgical instruments. The operators that performed this procedure all watched tutorial videos by Acland on the preconditions of microsurgical skills (1981) and basic microsuture technique (1985). We recommend practicing the surgical procedure 8&#8722;10 times before using it in research. Practicing the procedure ensures that fewer mistakes are made and that the procedure can be performed more efficiently. When mastered, the surgical procedure can be performed in 45 minutes.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>10-0 Nylon suture</td>
			<td>S&#38;T</td>
			<td>12051-10</td>
			<td></td>
		</tr>
		<tr>
			<td>6-0 Nylon suture - Dafilon</td>
			<td>B Braun</td>
			<td>C0933112</td>
			<td></td>
		</tr>
		<tr>
			<td>Coagulator - ICC 50</td>
			<td>ERBE</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton tipped applicators</td>
			<td>Yibon medical co</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting forceps</td>
			<td>Lawton</td>
			<td>09-0190</td>
			<td></td>
		</tr>
		<tr>
			<td>Elastic retractors</td>
			<td>Odense University Hospital</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Electrical clipper</td>
			<td>Aesculap</td>
			<td>GT420</td>
			<td></td>
		</tr>
		<tr>
			<td>Fentanyl 0,315 mg/ml</td>
			<td>Matrix</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Heating pad - PhysioSuite</td>
			<td>Kent Scientific Corp.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane 1000mg Attane</td>
			<td>Scan Vet</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane vaporizer - PPV</td>
			<td>Penlon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro jewler forceps</td>
			<td>Lawton</td>
			<td>1405-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Needle holder</td>
			<td>Lawton</td>
			<td>25679-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro scissors</td>
			<td>Lawton</td>
			<td>10128-15</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro tying forceps</td>
			<td>Lawton</td>
			<td>43953-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Microfine U-40 syringe 0,5ml</td>
			<td>BD</td>
			<td>328821</td>
			<td></td>
		</tr>
		<tr>
			<td>Microlance syringe 25g</td>
			<td>BD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microlance syringe 27g</td>
			<td>BD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Midazolam 5 mg/ml (hameln)</td>
			<td>Matrix</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Needle holder - Circle wood</td>
			<td>Lawton</td>
			<td>08-0065</td>
			<td></td>
		</tr>
		<tr>
			<td>Non woven swabs</td>
			<td>Selefa</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Opmi pico microscope F170</td>
			<td>Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Patent blue V - 25 mg/ml</td>
			<td>Guerbet</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors - Joseph</td>
			<td>BD</td>
			<td>RH1630</td>
			<td></td>
		</tr>
		<tr>
			<td>Siemens INVEON multimodality pre-clinical scanner</td>
			<td>Siemens pre-clinical solutions</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Source of radiation - D3100</td>
			<td>Gulmay</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stata Statistical Software: Release 15</td>
			<td>StataCorp LLC</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Temgesic - 0,2 mg</td>
			<td>Indivior</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vet eye ointment - viscotears</td>
			<td>Bausch &#38; Lomb</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

a revised method for inducing secondary lymphedema in the hindlimb of mice

Animal models are of paramount importance in the research of lymphedema in order to understand the pathophysiology of the disease but also to explore potential treatment options. This mouse model allows researchers to induce significant lymphedema lasting at least 8 weeks. Lymphedema is induced using a combination of fractioned radiotherapy and surgical ablation of lymphatics. This model requires that the mice get a dose of 10 Gray (Gy) radiation before and after surgery. The surgical part of the model involves ligation of three lymph vessels and extraction of two lymph nodes from the mouse hindlimb. Having access to microsurgical tools and a microscope is essential, due to the small anatomical structures of mice. The advantage of this model is that it results in statistically significant lymphedema, which provides a good basis for evaluating different treatment options. It is also a great and easily available option for microsurgical training. The limitation of this model is that the procedure can be time consuming, especially if not practiced in advance. The model results in objectively quantifiable lymphedema in mice, without causing severe morbidity and has been tested in three separate projects.

This procedure has previously been used in three separate experiments. All the experiments were made by different lead investigators who all are co-authors of this article. In all three experiments, great care was taken to adhere to the same procedure as described in this protocol. In all three experiments, secondary lymphedema was induced in one hindlimb while the other hindlimb served as a control. Volumes of the hindlimbs were the primary outcome in all three experiments. <strong class...

Watch this Scientific Journal Video about A Revised Method for Inducing Secondary Lymphedema in the Hindlimb of Mice at JoVE.com

A Revised Method for Inducing Secondary Lymphedema in the Hindlimb of Mice

This animal model enables researchers to induce statistically significant secondary lymphedema in the hindlimb of mice, lasting at least 8 weeks. The model can be used to study the pathophysiology of lymphedema and to investigate novel treatment options.

Animal models are of paramount importance in the research of lymphedema in order to understand the pathophysiology of the disease but also to explore ...

The overall goal of this method is to induce consistent secondary lymphedema in the hindlimb of mice without causing severe morbidity. This method can be used to induce secondary lymphedema in the hindlimb of mice. The main advantage of this method is that it resolves insignificant lymphedema lasting at least eight weeks without causing severe morbidity.Someone new to the procedure may struggle with the microsurgical techniques. We therefore recommend microsurgical training and several practice procedures to ensure a successful result, but also to prepare the researcher so that he or she can perform the procedure more efficiently. Set up the source of radiation and anesthetize the mouse as described in the protocol.Place a 1.5 millimeter thick lead pad to ensure that only the area that undergoes surgery gets irradiated. The shown example is of a post-surgery mouse to clarify the area. Administer a dose of 10 gray irradiation.The researchers must take precautions when working with radiation. During this experiment all irradiation was performed in a radiation insulated room. And the source of radiation was only turned on when all personnel had left the room.Weigh the mouse pre-surgery. Examine anesthetic depth by paw or tail pinch test. Shave the leg chosen for the procedure.Set the flow of oxygen to 0.8 Liters per minute. Connect it with a nose cone. Apply ophthalmic ointment.Inject 0.5 milliliters of saline subcutaneously, preferably in the scruff of the mouse to prevent hypovolemia during surgery. Place the mouse on the surgical cloth in supine position. Place the nose cone over the snout.Fixate the end of the hindlimbs gently with tape, to prevent the mouse from shifting during surgery. Lift the skin with smooth forceps and clip a small opening approximately five millimeters proximal to the popliteal fossa. Slide sharp scissors into the opening and clip towards the knee, so that the incision ends just above the knee.Make sure not to puncture the underlying vessels, by lifting the skin with forceps while clipping. Move the mouse to prone position and complete the circumferential incision. Dissect the skin to a couple of millimeters above the angle.Remember to keep the tissue damp with sterile saline during the whole procedure. Retract the skin of the proximal woundage with an elastic retractor. And make sure the sciatic vein is visible as shown.Inject 0.01 milliliters Patent Blue V subcutaneously between the second and third toe. Gently press the paw a couple of times to distribute the Patent Blue V.The distribution of the Patent Blue V can be seen through the microscope. The structures needed to be visualized are, the proximal lymph vessel, PLV, the popliteal lymph node, PLN, the first distal lymph vessel, DLV1, and the second distal lymph vessel, DLV2.Magnify to visualize the PLV and ligate it using a 10-0 nylon suture. Press the paw to ensure no Patent Blue passes proximal to the ligature. Ligate the two distal lymph vessels as shown.Press the paw several times again to make sure that no Patent Blue V passes proximal to the ligature. In this example, it can be seen that one of the lymph vessels bursts due to the ligature hindering the lymph flow. Remove the popliteal lymph node, the lymph node has a smooth pearl-like surface and is colored by the Patent Blue V in contrast to the surrounding fat tissue.Before removing the inguinal fat pad, cauterize this vessel as shown. Then remove the fat pad in one piece. Make sure that there is no active bleeding.This is an example of a located inguinal lymph node. The lymph node located in the inguinal fat pad is rarely colored by the Patent Blue V and can be hard to differentiate from the fat. Removing the fat pad in one piece is the best way to ensure that the lymph node has been removed.Suture the skin edges down to the muscle fascia, with a 6-0 nylon suture using forceps and needle holder, leaving a gap of two to three millimeters, to constrain the superficial lymph flow. This is an example of the finished sutures, in the popliteal fossa, the lateral side of the hindlimb, above the knee, and the medial side of the hindlimb. Administer analgesia and weigh the mouse post-surgery, then place it in a cabinet heated for recovery.Repeat the procedure for pre-surgery irradiation. This graph shows the combined mean hindlimb volume of three separate studies in the eight weeks after surgery. 31 mice were included in total.The x-axis represents weeks after surgery. The y-axis represents hindlimb volume in cubic millimeters. The arrow bars represent the standard deviation.It is to be expected that the swelling from the surgery and the induced lymphedema will decrease during the first four weeks. After the first four weeks we see a relative stable state of lymphedema. The volume of the control hindlimb increases during the eight weeks, thus strictly saying the difference in volume between the lymphedema hindlimb and the control hindlimb, this was unexpected.The cause is speculated to be that the mice used their non-operated hindlimb more than the operated hindlimb in the weeks following surgery. This could lead to hypertrophy of the control hindlimb and maybe explain the increase in volume. For individual figures on the three studies included please read the protocol.This table shows Sidak's multiple comparison test for the combined volume measurements of the three included studies. The calculated P-value shows that there is statistically significant difference between the hindlimbs with induced lymphedema and the control hindlimbs, during all eight weeks of follow up. For individual statistical analysis on the three included projects please read the protocol.This method induces statistically significant lymphedema, lasting at least eight weeks. The procedure can be used to study the petrificiality of lymphedema and to research novel treatment options. After watching this video, you should have gained an understanding of how to induce secondary lymphedema in the hindlimb of mice, using a combination of microsurgery and pre and post-surgery irradiation.Once mastered, the surgical procedure can be performed in 45 minutes.

a-revised-method-for-inducing-secondary-lymphedema-hindlimb

Research

JoVE Journal

Medicine

7.8K ビュー.  University of Southern Denmark. この方法の全体的な目標は、重篤な罹患率を引き起こすことなく、マウスの後肢に一貫した二次性リンパ浮腫を誘導することです。この方法は、マウスの後肢に二次リンパ浮腫を誘導するために使用することができる。この方法の主な利点は、重度の罹患率を引き起こすことなく、少なくとも8週間持続する重要でないリンパ浮腫を解決することです。処置に新しい...

ビデオ: A Revised Method for Inducing Secondary Lymphedema in the Hindlimb of Mice

A Simple Guide Screw Method for Intracranial Xenograft Studies in Mice

The grafting of human tumor cells into the brain of immunosuppressed mice is an established method for the study of brain cancers including glioblastoma (glioma) and medulloblastoma. The widely used stereotactic approach only allows for the injection of a single animal at a time, is labor intensive and requires highly specialized equipment. The guide screw method, initially developed by Lal et al.,1 was developed to eliminate cumbersome stereotactic procedures. We now describe a modified guide screw approach that is rapid and exceptionally safe; both of which are critical ethical considerations. Notably, our procedure now incorporates an infusion pump that allows up to 10 animals to be simultaneously injected with tumor cells.
To demonstrate the utility of this procedure, we established human U87MG glioma cells as intracranial xenografts in mice, which were then treated with AMG102; a fully human antibody directed to HGF/scatter factor currently undergoing clinical evaluation2-5. Systemic injection of AMG102 significantly prolonged the survival of all mice with intracranial U87MG xenografts and resulted in a number of complete cures. 
This study demonstrates that the guide screw method is an inexpensive, highly reproducible approach for establishing intracranial xenografts. Furthermore, it provides a relevant physiological model for validating novel therapeutic strategies for the treatment of brain cancers.

In order to evaluate novel therapeutic paradigms for the treatment of glioma, physiological relevant models are essential. We utilize an implantable guide screw procedure for establishment of intracranial xenograft models that is more rapid and safer than stereotactic approaches.

The grafting of human tumor cells into the brain of immunosuppressed mice is an established method for the study of brain cancers including glioblastoma ...

The Trier Social Stress Test Protocol for Inducing Psychological Stress

This article demonstrates a psychological stress protocol for use in a laboratory setting. Protocols that allow researchers to study the biological pathways of the stress response in health and disease are fundamental to the progress of research in stress and anxiety.1 Although numerous protocols exist for inducing stress response in the laboratory, many neglect to provide a naturalistic context or to incorporate aspects of social and psychological stress. Of psychological stress protocols, meta-analysis suggests that the Trier Social Stress Test (TSST) is the most useful and appropriate standardized protocol for studies of stress hormone reactivity.2 In the original description of the TSST, researchers sought to design and evaluate a procedure capable of inducing a reliable stress response in the majority of healthy volunteers.3 These researchers found elevations in heart rate, blood pressure and several endocrine stress markers in response to the TSST (a psychological stressor) compared to a saline injection (a physical stressor).3 Although the TSST has been modified to meet the needs of various research groups, it generally consists of a waiting period upon arrival, anticipatory speech preparation, speech performance, and verbal arithmetic performance periods, followed by one or more recovery periods. The TSST requires participants to prepare and deliver a speech, and verbally respond to a challenging arithmetic problem in the presence of a socially evaluative audience.3 Social evaluation and uncontrollability have been identified as key components of stress induction by the TSST.4 In use for over a decade, the goal of the TSST is to systematically induce a stress response in order to measure differences in reactivity, anxiety and activation of the hypothalamic-pituitary-adrenal (HPA) or sympathetic-adrenal-medullary (SAM) axis during the task.1 Researchers generally assess changes in self-reported anxiety, physiological measures (e.g. heart rate), and/or neuroendocrine indices (e.g. the stress hormone cortisol) in response to the TSST. Many investigators have adopted salivary sampling for stress markers such as cortisol and alpha-amylase (a marker of autonomic nervous system activation) as an alternative to blood sampling to reduce the confounding stress of blood-collection techniques. In addition to changes experienced by an individual completing the TSST, researchers can compare changes between different treatment groups (e.g. clinical versus healthy control samples) or the effectiveness of stress-reducing interventions.1

This article describes a protocol for inducing psychological stress in participants, which enables researchers to measure psychological, physiological and neuroendocrine responses to stress within single participants or between groups.

This article demonstrates a psychological stress protocol for use in a laboratory setting.  Protocols that allow researchers to study the biological ...

Inducing Myointimal Hyperplasia Versus Atherosclerosis in Mice: An Introduction of Two Valid Models

Various in vivo laboratory rodent models for the induction of artery stenosis have been established to mimic diseases that include arterial plaque formation and stenosis, as observed for example in ischemic heart disease. Two highly reproducible mouse models&#160;&#8211;&#160;both resulting in artery stenosis but each underlying a different pathway of development&#160;&#8211; are introduced here. The models represent the two most common causes of artery stenosis; namely one mouse model for each myointimal hyperplasia, and atherosclerosis are shown. To induce myointimal hyperplasia, a balloon catheter injury of the abdominal aorta is performed. For the development of atherosclerotic plaque, the ApoE -/- mouse model in combination with western fatty diet is used. Different model-adapted options for the measurement and evaluation of the results are named and described in this manuscript. The introduction and comparison of these two models provides information for scientists to choose the appropriate artery stenosis model in accordance to the scientific question asked.

This video shows two models of intimal plaque development in murine arteries and emphasizes the differences in myointimal hyperplasia and atherosclerosis.

Various in vivo laboratory rodent models for the induction of artery stenosis have been established to mimic diseases that include arterial plaque ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Minimal Invasive Surgical Procedure of Inducing Myocardial Infarction in Mice

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last decades. For clarification of the underlying mechanisms and the development of new therapeutic strategies, the availability of valid animal models are mandatory. Since we need new insights into pathomechanisms of cardiovascular diseases under in vivo conditions to combat myocardial infarction, the validity of the animal model is a crucial aspect. However, protection of animals are highly relevant in this context. Therefore, we establish a minimally invasive and simple model of myocardial infarction in mice, which assures a high reproducibility and survival rate of animals. Thus, this models fulfils the requirements of the 3R principle (Replacement, Refinement and Reduction) for animal experiments and assure the scientific information needed for further developing of therapeutical strategies for cardiovascular diseases.

A highly reproducible model for myocardial infarction in mice with minimal invasive manipulations is described. The model can be easily performed, resulting in a high reproducibility and survival rate. Thus, the described model will reduce the number of required animals as requested by the 3R principle (Replacement, Refinement and Reduction).

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last ...

An Improved Method for Rapid Intubation of the Trachea in Mice

Despite some anatomical and physiological differences, mouse models continue to be an essential tool for studying human lung disease. Bleomycin toxicity is a commonly used model to study both acute lung injury and fibrosis, and multiple methods have been developed for administering bleomycin (and other toxic agents) into the lungs. However, many of these approaches, such as transtracheal instillation, have inherent drawbacks, including the need for strong anesthetics and survival surgery. This paper reports a quick, reproducible method of intratracheal intubation that involves mild inhaled anesthesia, visualization of the trachea, and the use of a surrogate spirometer to confirm exposure. As a proof of concept, 8-12 week old C57BL/6 mice were administered either 2.0 U/kg of bleomycin or an equivalent volume of PBS, and both damage and fibrotic endpoints were measured post-exposure. This procedure allows researchers to treat a large cohort of mice in a relatively short period with little expense and minimal post-procedure care.

This article presents a rapid and simple method for administering bleomycin directly into the mouse trachea via intubation. Key advantages of this method are that it is highly reproducible, easy to master, and does not require specialized equipment or lengthy recovery times.

Despite some anatomical and physiological differences, mouse models continue to be an essential tool for studying human lung disease. Bleomycin toxicity ...

Assessing Therapeutic Angiogenesis in a Murine Model of Hindlimb Ischemia

Critical limb ischemia (CLI) is a serious condition that entails a high risk of lower limb amputation. Despite revascularization being the gold-standard therapy, a considerable number of CLI patients are not suited for either surgical or endovascular revascularization. Angiogenic therapies are emerging as an option for these patients but are currently still under investigation. Before application in humans, those therapies must be tested in animal models and its mechanisms must be clearly understood. An animal model of hindlimb ischemia (HLI) has been developed by the ligation and excision of the distal external iliac and femoral arteries and veins in mice. A comprehensive panel of tests was assembled to assess the effects of ischemia and putative angiogenic therapies at functional, histologic and molecular levels. Laser Doppler was used for the flow measurement and functional assessment of perfusion. Tissue response was evaluated by the analysis of capillary density after staining with the anti-CD31 antibody on histological sections of gastrocnemius muscle and by measurement of collateral vessel density after diaphonization. Expression of angiogenic genes was quantified by RT-PCR targeting selected angiogenic factors exclusively in endothelial cells (ECs) after laser capture microdissection from mice gastrocnemius muscles. These methods were sensitive in identifying differences between ischemic and non-ischemic limbs and between treated and non-treated limbs. This protocol provides a reproducible model of CLI and a framework for testing angiogenic therapies.

Here, a critical hindlimb ischemia experimental model is presented followed by a battery of functional, histologic and molecular tests&#160;to assess the effectiveness of angiogenic therapies.&#8203;

Critical limb ischemia (CLI) is a serious condition that entails a high risk of lower limb amputation. Despite revascularization being the gold-standard ...

Integrating Augmented Reality Tools in Breast Cancer Related Lymphedema Prognostication and Diagnosis

Breast cancer related lymphedema (BCRL) is a detrimental condition characterized by fluid accumulation in the upper limb in breast cancer patients subjected to axillary surgery and/or radiations. Its etiology is multifactorial and include also tumor-specific pathological features, such as lymphovascular invasion (LVI) and extranodal extension (ENE). To date, no widely employed guidelines for the early diagnosis of BCRL are available. Here, we illustrate a protocol for a digitally assisted BCRL assessment using a 3D laser scanner (3DLS) and a tablet computer. It has been specifically optimized in a discovery cohort of high-risk breast cancer patients. This study provides a proof-of-principle that augmented reality tools, such as 3DLS, can be incorporated into the clinical workup of BCRL to allow for a precise, reproducible, reliable, and cheap diagnosis.

Breast cancer related lymphedema is frequent in breast cancer survivors, but there are not widely employed guidelines for its diagnosis and quantification. Here, we introduce a reliable and cost-effective protocol to define, quantify, and compare upper limb volume in breast cancer patients.

Breast cancer related lymphedema (BCRL) is a detrimental condition characterized by fluid accumulation in the upper limb in breast cancer patients ...

A High-Throughput In Situ Method for Estimation of Hepatocyte Nuclear Ploidy in Mice

When the liver is injured, hepatocyte numbers decrease, while cell size, nuclear size and ploidy increase. The expansion of non-parenchymal cells such as cholangiocytes, myofibroblasts, progenitors and inflammatory cells also indicate chronic liver damage, tissue remodeling and disease progression. In this protocol, we describe a simple high-throughput approach for calculating changes in the cellular composition of the liver that are associated with injury, chronic disease and cancer. We show how information extracted from two-dimensional (2D) tissue sections can be used to quantify and calibrate hepatocyte nuclear ploidy within a sample and enable the user to locate specific ploidy subsets within the liver in situ. Our method requires access to fixed/frozen liver material, basic immunocytochemistry reagents and any standard high-content imaging platform. It serves as a powerful alternative to standard flow cytometry techniques, which require disruption of freshly collected tissue, loss of spatial information and potential disaggregation bias.

We present a robust, cost-effective, and flexible method for measuring changes in hepatocyte number and nuclear ploidy within fixed/cryopreserved tissue samples that does not require flow cytometry. Our approach provides a powerful sample-wide signature of liver cytology ideal for tracking the progression of liver injury and disease.

When the liver is injured, hepatocyte numbers decrease, while cell size, nuclear size and ploidy increase. The expansion of non-parenchymal cells such as ...

A Murine Tail Lymphedema Model

Lymphedema is extremity swelling caused by lymphatic dysfunction. The affected limb enlarges because of accumulation of fluid, adipose, and fibrosis. There is no cure for this disease. A mouse tail model that uses a focal full thickness skin excision near the base of the tail, resulting in tail swelling, has been used to study lymphedema. However, this model may result in vascular comprise and consequent tail necrosis and early tail swelling resolution, limiting its clinical translatability. The chronic murine tail lymphedema model induces sustained lymphedema over 15 weeks and a reliable perfusion to the tail. Enhancements of the traditional murine tail lymphedema model include 1) precise full thickness excision and lymphatic clipping using a surgical microscope, 2) confirmation of post-operative arterial and venous perfusion using high resolution laser speckle, and 3) functional assessment using indocyanine green near infrared laser lymphangiography. We also use tissue nanotransfection technology (TNT) for novel non-viral, transcutaneous, focal delivery of genetic cargo to the mouse tail vasculature.

Lymphedema is extremity swelling caused by lymphatic dysfunction. We describe a chronic murine tail model of lymphedema and the novel use of tissue nanotransfection technology (TNT) for genetic cargo delivery to the tail.

Lymphedema is extremity swelling caused by lymphatic dysfunction. The affected limb enlarges because of accumulation of fluid, adipose, and fibrosis. ...