This work was supported by NSFC grant 81800928, Research Funding from the West China School/Hospital of Stomatology Sichuan University (No. RCDWJS2021-1), and the State Key Laboratory of Oral Diseases Open Funding grant SKLOD-R013.

This study was approved by the Institutional Animal Care and Use Committee at the State Key Laboratory of Oral Diseases, Sichuan University. Permission was obtained from relevant local agencies before the experiment. Eight 8-10 week old male Sprague-Dawley (SD) rats, with an average weight of 200-250 g, were used for the present study. The animals were obtained from a commercial source (see Table of Materials). Food and water were provided ad libitum throughout the experimental period.
<p cl...

<ol>
	<li>Bilezikian, J. 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=Hypoparathyroidism+in+the+adult:+Epidemiology,+diagnosis,+pathophysiology,+target-organ+involvement,+treatment,+and+challenges+for+future+research.">Hypoparathyroidism in the adult: Epidemiology, diagnosis, pathophysiology, target-organ involvement, treatment, and challenges for future research.</a> Journal of Bone and Mineral Research. 26 (10), 2317-2337 (2011).</li><li>Bilezikian, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypoparathyroidism.">Hypoparathyroidism.</a> The Journal of Clinical Endocrinology and Metabolism. 105 (6), 1722-1736 (2020).</li><li>Underbjerg, L., Sikjaer, T., Mosekilde, L., Rejnmark, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postsurgical+hypoparathyroidism-Risk+of+fractures,+psychiatric+diseases,+cancer,+cataract,+and+infections.">Postsurgical hypoparathyroidism-Risk of fractures, psychiatric diseases, cancer, cataract, and infections.</a> Journal of Bone and Mineral Research. 29 (11), 2504-2510 (2014).</li><li>Underbjerg, L., Sikjaer, T., Mosekilde, L., Rejnmark, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+epidemiology+of+nonsurgical+hypoparathyroidism+in+Denmark:+A+nationwide+case+finding+study.">The epidemiology of nonsurgical hypoparathyroidism in Denmark: A nationwide case finding study.</a> Journal of Bone and Mineral Research. 30 (9), 1738-1744 (2015).</li><li>Astor, M. C., 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=Epidemiology+and+health-related+quality+of+life+in+hypoparathyroidism+in+Norway.">Epidemiology and health-related quality of life in hypoparathyroidism in Norway.</a> The Journal of Clinical Endocrinology and Metabolism. 101 (8), 3045-3053 (2016).</li><li>Rodriguez-Ortiz, M. 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=Calcium+deficiency+reduces+circulating+levels+of+FGF23.">Calcium deficiency reduces circulating levels of FGF23.</a> Journal of the American Society of Nephrology. 23 (7), 1190-1197 (2012).</li><li>Davies, B. M., Gordon, A. H., Mussett, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+plasma+calcium+assay+for+parathyroid+hormone,+using+parathyroidectomized+rats.">A plasma calcium assay for parathyroid hormone, using parathyroidectomized rats.</a> The Journal of Physiology. 125 (2), 383-395 (1954).</li><li>Clarke, B. 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=Epidemiology+and+diagnosis+of+hypoparathyroidism.">Epidemiology and diagnosis of hypoparathyroidism.</a> The Journal of Clinical Endocrinology and Metabolism. 101 (6), 2284-2299 (2016).</li><li>Liu, Y., Shan, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expert+consensus+on+diagnosis+and+treatment+for+elderly+with+thyroid+diseases+in+China.">Expert consensus on diagnosis and treatment for elderly with thyroid diseases in China.</a> Aging Medicine. 4 (2), 70-92 (2021).</li><li>Sulejmanovic, M., Cickusic, A. J., Salkic, S., Bousbija, F. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Annual+incidence+of+thyroid+disease+in+patients+who+first+time+visit+department+for+thyroid+diseases+in+Tuzla+Canton.">Annual incidence of thyroid disease in patients who first time visit department for thyroid diseases in Tuzla Canton.</a> Materia Socio-Medica. 31 (2), 130-134 (2019).</li><li>Liao, H. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+between+fibroblast+growth+factor+23+and+biochemical+and+bone+histomorphometric+alterations+in+a+chronic+kidney+disease+rat+model+undergoing+parathyroidectomy.">Relationship between fibroblast growth factor 23 and biochemical and bone histomorphometric alterations in a chronic kidney disease rat model undergoing parathyroidectomy.</a> PloS One. 10 (7), 0133278 (2015).</li><li>Russell, P. S., Gittes, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parathyroid+transplants+in+rats:+A+comparison+of+their+survival+time+with+that+of+skin+grafts.">Parathyroid transplants in rats: A comparison of their survival time with that of skin grafts.</a> The Journal of Experimental Medicine. 109 (6), 571-588 (1959).</li><li>Sakai, A., 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=Osteoclast+development+in+immobilized+bone+is+suppressed+by+parathyroidectomy+in+mice.">Osteoclast development in immobilized bone is suppressed by parathyroidectomy in mice.</a> Journal of Bone and Mineral Metabolism. 23 (1), 8-14 (2005).</li><li>Bi, R., Fan, Y., Luo, E., Yuan, Q., Mannstadt, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two+techniques+to+create+hypoparathyroid+mice:+parathyroidectomy+using+GFP+glands+and+diphtheria-toxin-mediated+parathyroid+ablation.">Two techniques to create hypoparathyroid mice: parathyroidectomy using GFP glands and diphtheria-toxin-mediated parathyroid ablation.</a> Journal of Visualized Experiments. (121), e55010 (2017).</li><li>Bi, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diphtheria+toxin-+and+GFP-based+mouse+models+of+acquired+hypoparathyroidism+and+treatment+with+a+long-acting+parathyroid+hormone+analog.">Diphtheria toxin- and GFP-based mouse models of acquired hypoparathyroidism and treatment with a long-acting parathyroid hormone analog.</a> Journal of Bone and Mineral Research. 31 (5), 975-984 (2016).</li><li>Huang, 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=Carbon+nanoparticles+suspension+injection+for+photothermal+therapy+of+xenografted+human+thyroid+carcinoma+in+vivo.">Carbon nanoparticles suspension injection for photothermal therapy of xenografted human thyroid carcinoma in vivo.</a> MedComm. 1 (2), 202-210 (2020).</li><li>Zhang, R. J., Chen, Y. L., Deng, X., Yang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+nanoparticles+for+thyroidectomy+and+central+lymph+node+dissection+for+thyroid+cancer.">Carbon nanoparticles for thyroidectomy and central lymph node dissection for thyroid cancer.</a> The American Surgeon. , (2022).</li><li>Long, 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=A+carbon+nanoparticle+lymphatic+tracer+protected+parathyroid+glands+during+radical+thyroidectomy+for+papillary+thyroid+non-microcarcinoma.">A carbon nanoparticle lymphatic tracer protected parathyroid glands during radical thyroidectomy for papillary thyroid non-microcarcinoma.</a> Surgical Innovation. 24 (1), 29-34 (2017).</li><li>Li, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+and+safety+of+long-term+universal+salt+iodization+on+thyroid+disorders:+Epidemiological+evidence+from+31+provinces+of+mainland+China.">Efficacy and safety of long-term universal salt iodization on thyroid disorders: Epidemiological evidence from 31 provinces of mainland China.</a> Thyroid. 30 (4), 568-579 (2020).</li><li>Powers, J., Joy, K., Ruscio, A., Lagast, H. <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+incidence+of+hypoparathyroidism+in+the+United+States+using+a+large+claims+database.">Prevalence and incidence of hypoparathyroidism in the United States using a large claims database.</a> Journal of Bone and Mineral Research. 28 (12), 2570-2576 (2013).</li><li>Zihao, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Promotion+of+allogeneic+parathyroid+cell+transplantation+in+rats+with+hypoparathyroidism.">Promotion of allogeneic parathyroid cell transplantation in rats with hypoparathyroidism.</a> Gland Surgery. 10 (12), 3403-3414 (2021).</li><li>Goncu, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenotransplantation+of+microencapsulated+parathyroid+cells+as+a+potential+treatment+for+autoimmune-related+hypoparathyroidism.">Xenotransplantation of microencapsulated parathyroid cells as a potential treatment for autoimmune-related hypoparathyroidism.</a> Experimental and Clinical Transplantation. , (2021).</li><li>Jung, S. 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=Standardization+of+a+physiologic+hypoparathyroidism+animal+model.">Standardization of a physiologic hypoparathyroidism animal model.</a> PLoS One. 11 (10), 0163911 (2016).</li><li>Chen, W., Lv, Y., Xie, R., Xu, D., Yu, J. <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+lymphatic+mapping+to+recognize+and+protect+parathyroid+in+thyroid+carcinoma+surgery+by+using+carbon+nanoparticles.">Application of lymphatic mapping to recognize and protect parathyroid in thyroid carcinoma surgery by using carbon nanoparticles.</a> Journal of Clinical Otorhinolaryngology, Head, and Neck Surgery. 28 (24), 1918-1920 (1924).</li></ol>

Epidemiological reports indicate that the detection of thyroid diseases has increased significantly, and the number of related surgeries performed has increased accordingly19,20. The incidence rate of postsurgical hypoparathyroidism is approximately 7.6%8,21, while the increased morbidity of acquired hypoparathyroidism has caused this rare disease to gain greater research attention. It is, therefore, part...

Parathyroid hormone (PTH) is secreted by the parathyroid glands. It is a major modulator of the calcium balance, maintains phosphate metabolism, and participates in bone turnover1,2. Hypoparathyroidism (HypoPT) manifests as a decreased secretion or functional loss of PTH. It is a rare endocrine disorder, with a prevalence of approximately 9-37 per 100,000 person-years3,4,5. HypoPT is characterized by decreased serum PTH and calcium levels accompanied by increased serum phosphorus6,7. HypoPT is classified based on its cause: acquired hypoparathyroidism (AHypoPT) or idiopathic hypoparathyroidism (IHypoPT)8. AHypoPT is more commonly encountered in clinical practice; about 75% of AHypoPT cases are caused by resection or accidental injury of the parathyroid glands during thyroid surgery or other head and neck surgeries. Other causes include radiotherapy and chemotherapy for head and neck tumors and drug toxicity1,8. Upgraded diagnostic methods and an increase in screening for thyroid gland-associated diseases have increased the number of thyroid gland surgical operations. This has led to a corresponding increase in the related parathyroid gland complications9,10.
Easily established animal models with stable characteristics are needed to better investigate AHypoPT and verify the therapeutic effectiveness of novel treatments. Parathyroidectomy (PTX) performed on rats and mice has been reported in previous studies6,11; however, due to the extremely small size of the parathyroid glands and the variability in their anatomical distribution, the success rate is relatively low in practice. Thus, thyro-parathyroidectomy (TPTX) (i.e., the total removal of the thyroid and parathyroid glands) is usually performed to ensure the resection of the parathyroid glands12. However, the resulting low thyroxine levels may complicate studies with this animal model13. HypoPT models established by other methods, such as drug stimulation and gene editing, cannot properly represent the most common AHypoPT pathogenesis. Our group previously used knockout mouse models to label the parathyroid glands and allow the removal of the parathyroid glands without damaging the thyroid glands and surrounding anatomical structures14,15. However, this method utilizes transgenic mouse models, which require a longer development time due to the mating and breeding requirements.
Therefore, we aimed to establish an easily generated model of AHypoPT. This study describes a rat model for PTX using carbon nanoparticle labeling. A carbon nanoparticle suspension of 50 mg/mL, which is commonly used in thyroid surgery, evenly distributes in the thyroid glands after local injection16. The thyroid glands turn black, but the parathyroid glands are left unstained17, thus clearly distinguishing the parathyroid glands from the thyroid glands and allowing the PTX to be performed without affecting the thyroid glands. This method is suitable for rats of different ages. The injection of the carbon nanoparticle suspension is safe and has a negligible effect on thyroid function18. The carbon nanoparticle-labeled PTX rat model generated in this study showed significant hypocalcemia and hyperphosphatemia phenotypes during the 4 week observation period. Thus, this AHypoPT model is easy to establish and has a reproducible phenotype.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.9% Sodium Chloride Solution</td>
			<td>Kelun Co. Sichuan, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>10 &#181;L 30G NanoFil Syringe</td>
			<td>WPI</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>6-0 polyglactin 910 suture with needle</td>
			<td>Ethicon, Inc</td>
			<td>J510G</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium LiquiColor test</td>
			<td>EKF</td>
			<td>0155-225</td>
			<td>For Ca2+ analysis</td>
		</tr>
		<tr>
			<td>Carbon Nanoparticles Suspension Injection</td>
			<td>Lummy, Chongqing, China</td>
			<td>H20073246</td>
			<td>1 mL : 50 mg</td>
		</tr>
		<tr>
			<td>Creatinine (Cr) Assay kit ( sarcosine oxidase )</td>
			<td>Jiancheng, Nanjing, China</td>
			<td>C011-2-1</td>
			<td>For creatinine analysis</td>
		</tr>
		<tr>
			<td>Disposable Scalpel</td>
			<td>Shinva, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dumstar Biology forceps</td>
			<td>Shinva, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Dissecting Spring Scissors</td>
			<td>Shinva, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MicroVue Rat intact PTH ELISA</td>
			<td>Immunotopics</td>
			<td>30-2531</td>
			<td>For the measurement of PTH in rat serum</td>
		</tr>
		<tr>
			<td>Needle Holder</td>
			<td>Shinva, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphorus Liqui-UV test</td>
			<td>EKF</td>
			<td>0830-125</td>
			<td>For Pi analysis</td>
		</tr>
		<tr>
			<td>Ply gauze</td>
			<td>Weian Co. Henan, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Povidone-Iodine</td>
			<td>Yongan pharmaceutical Co.Ltd. Chengdu, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Prism 9.0 (statistics and graphing software)</td>
			<td>GraphPad Software, Inc., San Diego, CA, USA</td>
			<td></td>
			<td>https://www.graphpad.com/scientific-software/prism/</td>
		</tr>
		<tr>
			<td>Rat C-telopeptide of type I collagen (CTX-I) ELISA Kit</td>
			<td>CUSABIO, Wuhan, China</td>
			<td>CSB-E12776r</td>
			<td>For CTX-I analysis</td>
		</tr>
		<tr>
			<td>Rat Osteocalcin/Bone Gla Protein (OT/BGP) ELISA Kit</td>
			<td>CUSABIO, Wuhan, China</td>
			<td>CSB-E05129r</td>
			<td>For osteocalcin analysis</td>
		</tr>
		<tr>
			<td>Safety Single Edge Razor Blades</td>
			<td>American Safety Razor Company</td>
			<td>66-0089</td>
			<td></td>
		</tr>
		<tr>
			<td>Sprague-Dawley Rats</td>
			<td></td>
			<td></td>
			<td>8 to 10 weeks old</td>
		</tr>
		<tr>
			<td>Surgical Incise Drapes</td>
			<td>Liangyou Co. Sichuan, China</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Urea Assay Kit</td>
			<td>Jiancheng, Nanjing, China</td>
			<td>C013-2-1</td>
			<td>For urea analysis</td>
		</tr>
	</tbody>
</table>

generation of hypoparathyroid rats via carbon-nanoparticle-assisted parathyroidectomy

Hypoparathyroidism (HypoPT) is a rare disease involving the parathyroid glands that is characterized by a reduced secretion or potency of the parathyroid hormone (PTH), which leads to high serum phosphorus levels and low serum calcium levels. HypoPT most commonly results from accidental damage to the glands or their removal during thyroid or other anterior neck surgery. Parathyroid/thyroid surgery has become more common in recent years, with a corresponding rise in the occurrence of HypoPT as a postoperative complication. There is a critical need for a HypoPT animal model to better understand the mechanisms underlying the effects of HypoPT on mineral ion homeostasis and to verify the therapeutic effectiveness of novel treatments. Here, a technique is reported to create acquired HypoPT in male rats by performing parathyroidectomy (PTX) using carbon nanoparticles. The rat model shows great promise over the mouse models of hypoparathyroidism.&#160;Importantly, the human PTH receptor binding region has an 84.2% sequence similarity with that of the rat, which is higher than the 73.7% similarity shared with mice. Moreover, the effects of estrogen, which can affect the PTH/PTHrP receptor signaling pathway, have not been fully investigated in male rats. Carbon nanoparticles are lymphatic tracers that stain the thyroid lymph nodes black without affecting their function, but they do not stain the parathyroid glands, which makes them easy to identify and remove. In this study, serum PTH levels were undetectable after PTX, and this resulted in significant hypocalcemia and hyperphosphatemia. Thus, the clinical state of postoperative HypoPT can be remarkably represented in the rat model. Carbon-nanoparticle-assisted PTX can, therefore, serve as an extraordinarily effective and readily implementable model for studying the pathogenesis, treatment, and prognosis of HypoPT.

The locations and number of parathyroid glands were initially observed in rats under a dissection microscope. Before the carbon nanoparticle injection, the thyroid glands were a translucent red color, and the parathyroid glands were hardly distinguishable under the microscope (Figure 1A). After the nanoparticle injection, the thyroid glands were stained black, while the parathyroid glands remained unstained (Figure 1B). The careful dissection of the light-colore...

Watch this Scientific Journal Video about Generation of Hypoparathyroid Rats via Carbon-Nanoparticle-Assisted Parathyroidectomy at JoVE.com

Generation of Hypoparathyroid Rats via Carbon-Nanoparticle-Assisted Parathyroidectomy

An animal model of acquired hypoparathyroidism (HypoPT) is crucial to understanding how HypoPT affects mineral ion homeostasis and to verify the effectiveness of novel treatments. Here, a technique is presented to generate an acquired hypoparathyroidism (AHypoPT) rat model by parathyroidectomy (PTX) using carbon nanoparticles.

Generation of Hypoparathyroid Rats via Carbon-Nanoparticle-Assisted Parathyroidectomy

Hypoparathyroidism (HypoPT) is a rare disease involving the parathyroid glands that is characterized by a reduced secretion or potency of the parathyroid ...

The overall goal of this protocol is to generate a rat model of acquired hypoparathyroidism that is easy to establish, stable in character, and harmless to the thyroid glands. The main advantage of this model is the precise removal of parathyroid glands with the assistance of carbon nanoparticles. We hope the model can help solve a few questions in the field of hypoparathyroidism.For example, preoperative use of calcium and vitamin D to reduce the risk of post-thyroidectomy hypocalcemia. This method can provide insight into how bone turnover is affected by PTH analogs and how PTH analogs affects the body in long-term use. Those who perform this technique for the first time may find it hard to micro-manipulate under the stereo microscope.Some practice under stereo microscope may be helpful. To begin, place the anesthetized rat in a supine position and shave the fur of the ventral neck region. After making an incision as described in the manuscript, locate the lobes of the thyroid gland.Using a 10-microliter syringe equipped with a 30-gauge bevel needle, inject one microliter of the carbon nanoparticle suspension into the mesial portion of the thyroid gland membrane. After five minutes, irrigate the region with saline to clean any extra suspension. Ensure the thyroid glands have turned black and observe the unstained parathyroid gland.Cut the unstained parathyroid glands using a pair of microsurgery forceps and scissors, and then close the incision with an interrupted horizontal mattress suture. After surgery, place the rats on a thermostatic electric blanket at 37 degrees Celsius to maintain their body temperature. After seven days, draw 10 microliters of blood using the tail vein.Measure the serum calcium, serum inorganic phosphorus, and serum parathyroid hormone using commercial kits. The parathyroidectomy rats displayed stable hypocalcemia and hyperphosphatemia over the observation period of four weeks. The serum parathyroid hormone was undetected in the parathyroidectomy rats seven days post-operation.The serum urea and creatinine were comparable between the sham and parathyroidectomy groups after seven days post-operation. Reduced urinary calcium ions and inorganic phosphate levels were observed two weeks post-operation. No significant differences in body weight were observed between the parathyroidectomy and sham groups across 28 days.The serum C-telopeptide decreased significantly in parathyroidectomy rats. There were no significant differences in the serum osteocalcin levels. However, nanoparticle suspension injection is the most important thing and a successful injection is critical for identification and present removal of the parathyroid glands.Other methods include fluorescence-guided surgery, diphteria toxin injection of PTHcre-iDTR transgenic mice, and the sterile parathyroidectomy which could help answer questions in the field of hyperthyroidism.

generation-hypoparathyroid-rats-via-carbon-nanoparticle-assisted

Research

JoVE Journal

Medicine

Acute Myocardial Infarction in Rats

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular diseases. Animal models that mimic human cardiac disease, such as myocardial infarction (MI) and ischemia-reperfusion (IR) that induces heart failure as well as pressure-overload (transverse aortic constriction) that induces cardiac hypertrophy and heart failure (Goldman and Tarnavski), are useful models to study cardiovascular disease. In particular, myocardial ischemia (MI) is a leading cause for cardiovascular morbidity and mortality despite controlling certain risk factors such as arteriosclerosis and treatments via surgical intervention (Thygesen). Furthermore, an acute loss of the myocardium following myocardial ischemia (MI) results in increased loading conditions that induces ventricular remodeling of the infarcted border zone and the remote non-infarcted myocardium. Myocyte apoptosis, necrosis and the resultant increased hemodynamic load activate multiple biochemical intracellular signaling that initiates LV dilatation, hypertrophy, ventricular shape distortion, and collagen scar formation. This pathological remodeling and failure to normalize the increased wall stresses results in progressive dilatation, recruitment of the border zone myocardium into the scar, and eventually deterioration in myocardial contractile function (i.e. heart failure). The progression of LV dysfunction and heart failure in rats is similar to that observed in patients who sustain a large myocardial infarction, survive and subsequently develops heart failure (Goldman). The acute myocardial infarction (AMI) model in rats has been used to mimic human cardiovascular disease; specifically used to study cardiac signaling mechanisms associated with heart failure as well as to assess the contribution of therapeutic strategies for the treatment of heart failure. The method described in this report is the rat model of acute myocardial infarction (AMI). This model is also referred to as an acute ischemic cardiomyopathy or ischemia followed by reperfusion (IR); which is induced by an acute 30-minute period of ischemia by ligation of the left anterior descending artery (LAD) followed by reperfusion of the tissue by releasing the LAD ligation (Vasilyev and McConnell). This protocol will focus on assessment of the infarct size and the area-at-risk (AAR) by Evan's blue dye and triphenyl tetrazolium chloride (TTC) following 4-hours of reperfusion; additional comments toward the evaluation of cardiac function and remodeling by modifying the duration of reperfusion, is also presented. Overall, this AMI rat animal model is useful for studying the consequence of a myocardial infarction on cardiac pathophysiological and physiological function.

The rat model of acute myocardial infarction (AMI) is useful to study the consequence of a MI on cardiac pathophysiological and physiological function.

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular ...

Generation of Alginate Microspheres for Biomedical Applications

Alginate-based materials have received considerable attention for biomedical applications because of their hydrophilic nature, biocompatibility, and physical architecture. Applications include cell encapsulation, drug delivery, stem cell culture, and tissue engineering scaffolds. In fact, clinical trials are currently being performed in which islets are encapsulated in PLO coated alginate microbeads as a treatment of type I diabetes. However, large numbers of islets are required for efficacy due to poor survival following transplantation. The ability to locally stimulate microvascular network formation around the encapsulated cells may increase their viability through improved transport of oxygen, glucose and other vital nutrients. Fibroblast growth factor-1 (FGF-1) is a naturally occurring growth factor that is able to stimulate blood vessel formation and improve oxygen levels in ischemic tissues. The efficacy of FGF-1 is enhanced when it is delivered in a sustained fashion rather than a single large-bolus administration. The local long-term release of growth factors from islet encapsulation systems could stimulate the growth of blood vessels directly towards the transplanted cells, potentially improving functional graft outcomes. In this article, we outline procedures for the preparation of alginate microspheres for use in biomedical applications. In addition, we describe a method we developed for generating multilayered alginate microbeads. Cells can be encapsulated in the inner alginate core, and angiogenic proteins in the outer alginate layer. The release of proteins from this outer layer would stimulate the formation of local microvascular networks directly towards the transplanted islets.

In the following sections, we outline procedures for the preparation of alginate microspheres for use in biomedical applications. We specifically illustrate a technique for creating multilayered alginate microspheres for the dual purpose of cell and protein encapsulation as a potential treatment for type 1 diabetes.

Alginate-based materials have received considerable attention for biomedical applications because of their hydrophilic nature, biocompatibility, and ...

Orthotopic Small Bowel Transplantation in Rats

Small bowel transplantation has become an accepted clinical option for patients with short gut syndrome and failure of parenteral nutrition (irreversible intestinal failure). In specialized centers improved operative and managing strategies have led to excellent short- and intermediate term patient and graft survival while providing high quality of life 1,3. Unlike in the more common transplantation of other solid organs (i.e. heart, liver) many underlying mechanisms of graft function and immunologic alterations induced by intestinal transplantation are not entirely known6,7. Episodes of acute rejection, sepsis and chronic graft failure are the main obstacles still contributing to less favorable long term outcome and hindering a more widespread employment of the procedure despite a growing number of patients on home parenteral nutrition who would potentially benefit from such a transplant. The small intestine contains a large number of passenger leucocytes commonly referred to as part of the gut associated lymphoid system (GALT) this being part of the reason for the high immunogenity of the intestinal graft. The presence and close proximity of many commensals and pathogens in the gut explains the severity of sepsis episodes once graft mucosal integrity is compromised (for example by rejection). To advance the field of intestinal- and multiorgan transplantation more data generated from reliable and feasible animal models is needed. The model provided herein combines both reliability and feasibility once established in a standardized manner and can provide valuable insight in the underlying complex molecular, cellular and functional mechanisms that are triggered by intestinal transplantation. We have successfully used and refined the described procedure over more than 5 years in our laboratory 8-11. The JoVE video-based format is especially useful to demonstrate the complex procedure and avoid initial pitfalls for groups planning to establish an orthotopic rodent model investigating intestinal transplantation.

Small bowel transplantation has become an accepted treatment option for patients with irreversible intestinal failure. Our experimental model of orthotopic small bowel transplantation in rats serves as a reliable tool to address underlying immunologic and inflammatory processes that complicate intestinal transplantation.

Small  bowel transplantation has become an accepted clinical option for patients with  short gut syndrome and failure of parenteral nutrition ...

Orthotopic Liver Transplantation in Rats

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat liver transplantation in 1979 by Kamada et al.3, this model has remained the gold standard despite various proposed alternative techniques4. Nevertheless, its broader use is limited by its steep learning curve5.
In this video paper, we show a simple and easy-to-establish revision of Kamada's two-cuff technique. The suprahepatic vena cava anastomosis is performed manually with a running suture, and the vena porta and infrahepatic vena cava anastomoses are performed utilizing a quick-linker cuff system6. Manufacturing the quick-linker kit is shown in a separate video paper.

We present an easy-to-establish revision of the classical two-cuff technique for orthotopic liver transplantation in rat.

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat ...

Histological Quantification of Chronic Myocardial Infarct in Rats

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ischemic injury. Following the initial acute phase, chronic remodeling of the left ventricle (LV) modifies the structure and function of the heart. Permanent coronary ligation in small animals has been widely used as a reference model for a chronic model of MI. Thinning of the infarcted wall progressively develops to transmural fibrosis. Histological assessment of infarct size is commonly performed; nevertheless, a standardization of the methods for quantification is missing. Indeed, important methodological aspects, such as the number of sections analyzed and the sampling and quantification methods, are usually not described and therefore preclude comparison across investigations. Too often, quantification is performed on a single section obtained at the level of the papillary muscles. Because novel strategies aimed at reducing infarct expansion and remodeling are under investigation, there is an important need for the standardization of accurate heart sampling protocols. We describe an accurate method to quantify the infarct size using a systematic sampling of harvested rat heart and image analyses of trichromatic stained histological sections obtained from base to apex. We also provide evidence that calculating the expansion index (EI) allowed for infarct size assessment, taking into account changes of the left ventricle throughout the remodeling.

The post-mortem assessment of myocardial infarction (MI) in rodents is based on quantification of the infarct on stained heart sections. We describe an accurate method to quantify the infarct size using systematic sampling of harvested rat hearts from base to apex and image analyses of trichrome-stained histological sections.

Myocardial infarction is defined as cardiomyocyte death due to prolonged ischemia; an inflammatory response and scar formation (fibrosis) follow the ...

Two Techniques to Create Hypoparathyroid Mice: Parathyroidectomy Using GFP Glands and Diphtheria-Toxin-Mediated Parathyroid Ablation

Hypoparathyroidism (HP) is a disorder characterized by low levels of PTH which lead to hypocalcemia, hyperphosphatemia, and low bone turnover. The most common cause of the disease is accidental removal of the parathyroid glands during thyroid surgery. Novel therapies for HP are needed, but testing them requires reliable animal models of acquired HP. 
Here, we demonstrate the generation of two mouse models of acquired HP. In the GFP-PTX model, mice with green fluorescent protein (GFP) expressed specifically in the parathyroids (PTHcre-mTmG) were created by crossing PTHcre+ mice with Rosa-mTmGfl/fl mice. Green fluorescing parathyroid glands are easily identified under a fluorescence dissecting microscope and parathyroidectomy is performed in less than 20 min. After fluorescence-guided surgery, mice are profoundly hypocalcemic. Contrary to the traditional thyro-parathyroidectomy, this precise surgical approach leaves thyroid glands and thyroid function intact. The second model, which does not require surgery, is based on a diphtheria-toxin approach. PTHcre-iDTR mice, which express the diphtheria toxin (DT) receptor specifically in the parathyroids, were generated by crossing the inducible DTR mouse with the PTHcre mouse. Parathyroid cells are thus rendered sensitive to diphtheria toxin (DT) and can be selectively destroyed by systemically injecting mice with DT. The resulting hypocalcemic phenotype is stable.

Mice with acquired hypoparathyroidism would be useful for studying novel drug therapies for hypoparathyroidism. Two procedures to create such mice are demonstrated. The GFP-PTX mouse is generated by surgical parathyroidectomy guided by green fluorescing parathyroid glands. A second, non-surgical approach is based on parathyroid-specific expression of the diphtheria toxin receptor.

Hypoparathyroidism (HP) is a disorder characterized by low levels of PTH which lead to hypocalcemia, hyperphosphatemia, and low bone turnover. The most ...

One-anastomosis Gastric Bypass (OAGB) in Rats

The goal of this protocol is to set up a preclinical model of bariatric surgery and, more specifically, OAGB in obese rats. Based on this preclinical model, longitudinal studies can be carried out to provide an improved understanding of the mechanisms underlying the outcomes seen after bariatric surgery in humans. For this purpose, rats are operated on through a laparotomy under general anesthesia with isoflurane. First, the surgeon creates a long and tubular gastric pouch: after greater curve and hiatal dissection, the nonglandular stomach is stapled and removed. Then, the remaining stomach is also stapled in order to create a gastric tube and exclude the antrum of the stomach. After that, the surgeon performs a single end-to-side gastrojejunostomy 35 cm from the duodenojejunal angle. This limb length has been chosen in order to reproduce the same ratio between the biliopancreatic limb (BPL) and common limb (CL) length as in human bariatric surgery. The operation ends by aponeurotic and cutaneous closure. The early postoperative management consists of subcutaneous hydration, an intramuscular prophylactic antibiotic injection, a parietal injection of xylocaine, the administration of painkillers, and a progressive reintroduction of diet.

One-anastomosis Gastric Bypass OAGB in Rats

This protocol is for the performance of one-anastomosis gastric bypass (OAGB) on rat. The operator performs a long and tubular-stapled gastric pouch followed by hand-sewn anastomosis. For this model, the operator reproduces the same ratio between biliopancreatic and common limb in humans; therefore, the biliopancreatic limb measures 35 cm.

The goal of this protocol is to set up a preclinical model of bariatric surgery and, more specifically, OAGB in obese rats. Based on this preclinical ...

Echocardiographic Assessment of Cardiac Anatomy and Function in Adult Rats

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional imaging to study the cardiac anatomy of the left ventricle and M-mode echo to assess its dimensions. However, this could limit a comprehensive study. Herein, we describe a protocol that allows an assessment of the heart chamber size, left ventricular function (systolic and diastolic) and valvular function. A conventional medical ultrasound machine was used in this protocol and different echo views were obtained through left parasternal, apical and suprasternal windows. In the left parasternal window, the long and short axis were acquired to analyze left chamber dimensions, right ventricle and pulmonary artery dimensions, and mitral, pulmonary and aortic valve function. The apical window allows the measurement of heart chamber dimensions and evaluation of systolic and diastolic parameters. It also allows Doppler assessment with detection and quantification of heart valve disturbances (regurgitation or stenosis). Different segments and walls of the left ventricle are visualized throughout all views. Finally, the ascending aorta, aortic arch, and descending aorta can be imaged through the suprasternal window. A combination of ultrasound imaging, Doppler flow and tissue Doppler assessment have been obtained to study cardiac morphology and function. This represents an important contribution to improve the assessment of cardiac function in adult rats with impact for research using these animal models.

A non-invasive protocol for transthoracic echocardiography assessment of cardiac anatomy and function for adult rats is presented in the current study. The heart valves, all four cardiac chambers and the ascending aorta, aortic arch and descending aorta are studied in detail.

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional ...

Inducing Acute Liver Injury in Rats via Carbon Tetrachloride (CCl4) Exposure Through an Orogastric Tube

Acute liver injury (ALI) plays a crucial role in the development of hepatic failure, which is characterized by severe liver dysfunction including complications such as hepatic encephalopathy and impaired protein synthesis. Appropriate animal models are vital to test the mechanism and pathophysiology of ALI and investigate different hepatoprotective strategies. Due to its ability to perform chemical transformations, carbon tetrachloride (CCl4) is widely used in the liver to induce ALI through the formation of reactive oxygen species. CCl4 exposure can be performed intraperitoneally, by inhalation, or through a nasogastric or orogastric tube. Here, we describe a rodent model, in which ALI is induced by CCl4 exposure through an orogastric tube. This method is inexpensive, easily performed, and has minimal hazard risk. The model is highly reproducible and can be widely used to determine the efficacy of potential hepatoprotective strategies and assess markers of liver injury.

Inducing Acute Liver Injury in Rats via Carbon Tetrachloride CCl4 Exposure Through an Orogastric Tube

This protocol describes a common and feasible method of inducing acute liver injury (ALI) via CCl4 exposure through an orogastric tube. CCl4 exposure induces ALI through the formation of reactive oxygen species during its biotransformation in the liver. This method is used to analyze the pathophysiology of ALI and examine different hepatoprotective strategies.

Acute liver injury (ALI) plays a crucial role in the development of hepatic failure, which is characterized by severe liver dysfunction including ...

Intratracheal Instillation of Stem Cells in Term Neonatal Rats

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

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

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