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.
1. Preoperative preparation for the generation of carbon-nanoparticle-assisted PTX rats
<ol>
	<li>Anesthetize the 8-10 week old rats using 2.0%-2.5% isoflurane inhalation, followed by an intraperitoneal (i.p.) injection of tribromoethanol at 10 mL/kg body weight. Guarantee a sufficient depth of anesthesia by testing the absence of the pupillary light reflex. Use vet ointment on the eyes to prevent dryness while under anesthesia. 
	&#8203;NOTE: Rats that are 8-10 weeks old are recognized as adult rats. However, this modeling method can be used on rats as young as 7 days old.</li>
	<li>Prepare the anesthetized SD rats for surgery by shaving the fur of the ventral neck region in the supine position. Disinfect the operative area using povidone-iodine cotton balls (see Table of Materials).</li>
	<li>Cover the animal with surgical drapes (see Table of Materials), and expose the surgical region, aiming to minimize microbial contamination.</li>
</ol>
2. Parathyroidectomy (PTX)
<ol>
	<li>Start at the midpoint between the two ears, and cut a 2 cm incision longitudinally toward the tail using a surgical scalpel. Dissect the fascia and fat layer successively with sharp, curved, serrated forceps.</li>
	<li>Separate the paratracheal muscles, and expose the trachea using relatively blunt forceps under a stereo microscope at 4x-5x magnification.</li>
	<li>Locate the left and right lobes of the butterfly-shaped thyroid glands by the side of the trachea.</li>
	<li>Inject 1 &#181;L of the carbon nanoparticle suspension (see Table of Materials) beneath the membrane of the thyroid glands using a 10 &#181;L syringe with a 30 G beveled needle. After 5 min, irrigate the operative region with saline to clean the extra carbon nanoparticle suspension covering the thyroid gland membrane. 
	NOTE: The recommended injection point is the mesial portion of the thyroid gland lobe, which has fewer blood vessels. A carbon nanoparticle suspension is commonly used in thyroid surgery due to its ability to detect the lymph nodes. Staining the thyroid glands and leaving the parathyroid glands unstained eases the identification of the latter.</li>
	<li>Check to ensure that the thyroid glands turn black while the parathyroid glands remain unstained in ~5 min. Observe the highlighted parathyroid glands under ordinary light using either the light of a stereo microscope or a table lamp. 
	NOTE: Typically, rodents have two drop-shaped parathyroid glands located on the left and right surfaces of the thyroid glands. Occasionally, additional parathyroid glands may be located further away.</li>
	<li>Precisely cut the unstained parathyroid glands with microsurgery forceps and scissors. Use sterile cotton balls for hemostasis or a gelatin sponge if there is more bleeding.</li>
	<li>Close the muscles, fat layers, and skin, layer by layer, with an interrupted horizontal mattress suture using 6-0 polyglactin 910 sutures (see Table of Materials).</li>
	<li>For the sham group, perform all the steps of the preoperative preparation and PTX except step 2.6. Anesthetize the rats, and separate the tissues above the trachea. Locate the parathyroid glands but do not remove them. Conduct postoperative recovery and observation together with the rats of the PTX group.</li>
</ol>
3. Postoperative recovery and observation
<ol>
	<li>After surgery, place the rats on a thermostatic electric blanket (37 &#176;C) to maintain their body temperature. Inject buprenorphine hydrochloride 0.01 mg/kg subcutaneously (s.c) every 12 h as postoperative analgesia. Transfer the rats to a sterile cage when they begin to move and try to crawl.&#160;</li>
	<li>Closely observe the rats postoperatively for 2 h. Return the rats to the rearing room, observe them routinely, and record their state.</li>
	<li>Draw 10 &#181;L of blood from the tail vein 7 days after the surgery. Measure the serum Ca2+, serum Pi, and serum PTH using appropriate commercial kits (see Table of Materials). A successful parathyroidectomy produces a reduced serum ionized Ca2+ level 2 SD lower than that of sham-operated rats (9.00 mmol/L, n = 16). 
	NOTE: A statistics and graphing software (see Table of Materials) was used for the statistical analysis. A Student&#39;s t-test was used to compare the serum and urinary parameters between the sham and PTX groups. p &#60; 0.05 was considered statistically significant. Serum and urinary Ca2+ and Pi and serum urea and creatinine were measured with commercial kits according to the manufacturers&#39; instructions (see Table of Materials). Serum C-telopeptide of type I collagen and osteocalcin were measured with commercially available ELISA kits (see Table of Materials).</li>
</ol>

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The authors declare that they have no competing financial interests.

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 ...

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1.7K Views.  Sichuan University. 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.

Video: Generation of Hypoparathyroid Rats via Carbon-Nanoparticle-Assisted Parathyroidectomy

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 ...

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 ...

Preparation of Decellularized Kidney Scaffolds in Rats

Tissue engineering is a cutting-edge discipline in biomedicine. Cell culture techniques can be applied for regeneration of functional tissues and organs to replace diseased or damaged organs. Scaffolds are needed to facilitate the generation of three-dimensional organs or tissues using differentiated stem cells in vivo. In this report, we describe a novel method for developing vascularized scaffolds using decellularized rat kidneys. Eight-week-old Sprague-Dawley rats were used in this study, and heparin was injected into the heart to facilitate flow into the renal vessels, allowing heparin to perfuse into the renal vessels. The abdominal cavity was opened, and the left kidney was collected. The collected kidneys were perfused for 9 h using detergents, such as Triton X-100 and sodium dodecyl sulfate, to decellularize the tissue. Decellularized kidney scaffolds were then gently washed with 1% penicillin/streptomycin and heparin to remove cellular debris and chemical residues. Transplantation of stem cells with the decellularized vascular scaffolds is expected to facilitate the generation of new organs. Thus, the vascularized scaffolds may provide a foundation for tissue engineering of organ grafts in the future.

This protocol introduces a method to develop a scaffold using decellularized rat kidneys. The protocol includes decellularization and recellularization processes to confirm bioavailability. Decellularization is performed using Triton X-100 and sodium dodecyl sulfate.

Tissue engineering is a cutting-edge discipline in biomedicine. Cell culture techniques can be applied for regeneration of functional tissues and organs ...

Multicolor Immunofluorescence of the Nasal Tissue in an Allergic Rhinitis Rat Model

Immunofluorescent Labeling in Nasal Mucosa Tissue Sections of Allergic Rhinitis Rats via Multicolor Immunoassay

Allergic rhinitis (AR) is a chronic, non-infectious inflammatory disease of the nasal mucosa, primarily mediated by specific immunoglobulin E (IgE), affecting approximately 10%-20% of the world's population. While immunofluorescence (IF) staining has long been a standard technique for detecting disease-specific protein expression, conventional IF techniques are limited in their ability to detect the expression levels of three or more proteins in the same sample. Consequently, multicolor IF techniques have been developed in recent years, which allow the simultaneous labeling of multiple targets in cells or tissues.
This protocol provides a comprehensive overview of the process for establishing a rat model of AR, obtaining nasal mucosal samples, and the technical procedures for multicolor immunofluorescence. All rats in the AR group exhibited typical symptoms such as sneezing, a runny nose, and an itchy nose, with behavioral observations scoring &#8805;5 points. Hematoxylin and eosin (H&amp;E) staining revealed increased inflammatory cell counts and disrupted nasal mucosal integrity in the AR group. Multicolor immunofluorescence (mIF) demonstrated increased expression of ROR&#947;t and TICAM-1, while Foxp3 expression decreased in the nasal mucosa tissue of AR rats.

Author Spotlight: Advancing Allergic Rhinitis Research with Multicolor Immunofluorescence

This protocol describes a multicolor immunofluorescence technique for evaluating the rat model of allergic rhinitis.

Allergic rhinitis (AR) is a chronic, non-infectious inflammatory disease of the nasal mucosa, primarily mediated by specific immunoglobulin E (IgE), ...