This work was funded by the National Natural Science Foundation of China (82003406), the Natural Science Foundation of Hebei Province (H2022209073), and the Science and Technology Project of Hebei Education Department (ZD2022127).

All animal experiments were conducted according to the United States National Institutes of Health Guide for the Care and Use of Laboratory Animals and approved by the Committee on the Ethics of North China University of Science and Technology (protocol code LX2019033 and 2019-3-3 of approval). Male Wistar rats, 3 weeks of age, were used for the present study. All rats were kept in static cages with wood shavings. The animals were maintained in a 12 h/12 h light/dark cycle, and were provided with food and water ad libitum. Follow-up experiments were conducted after 1 week of adaptive feeding.
1. Animal preparation
<ol>
	<li>Upon arrival, house all the rats in a specific pathogen-free (SPF) room.</li>
	<li>Randomly divide the healthy rats into two groups (n = 10): control rats inhaling pure air and rats with silicosis inhaling silica.</li>
</ol>
2. Silica preparation
CAUTION: Silica dust inhaled by the human body can damage the lungs. Therefore, individuals must wear overalls, medical gloves, and protective masks (N95) during operations.
<ol>
	<li>Ground the silica particles (see Table of Materials) with an agate mortar for 1.5 h before each exposure. This is because freshly fractured quartz produces larger quantities of active oxygen species than aged quartz13, and silica with a diameter of 1-5 &#181;m is the most pathogenic.</li>
	<li>Weigh the silica (30 g) using an electronic balance after grinding, place it in a glass container, and bake it at 180 &#176;C for 6 h in an electric heating air-blowing drier (see Table of Materials) to eliminate pathogens from the surface of the silica particles.</li>
</ol>
3. Silica exposure to the rats
<ol>
	<li>Connect the injection and the commercially available generator systems (see Table of Materials) and place the silica (30 g) in the generator. Check whether the connection pipeline is normal, the power cord is connected, and the power supply is normal.
	<ol>
		<li>Check the water level of the spray tower and the humidifier of the waste gas treatment device (see Table of Materials) manually, and add water if it is insufficient (not up to the standard line).</li>
		<li>Add tap water to the spray tower of the waste gas treatment device and distilled water to the humidifier (Figure 1).</li>
	</ol>
	</li>
	<li>Turn on the exhaust gas discharge device (see Table of Materials) and the air source switch to confirm whether the inside of the shielding cabinet is in a negative-pressure state.
	<ol>
		<li>Confirm that the liquid mixing, powder mixing, pure gas flow control valves, and wastewater discharge valve under the inhalation chamber are closed.</li>
	</ol>
	</li>
	<li>Place a total of 10 rats in the inhalation chamber (see Table of Materials), and close the inhalation compartment and the screened cabinet doors.</li>
	<li>Set the following experimental parameters on the instrument panel or in the computer: cabinet pressure: -50 to -30 Pa; oxygen concentration: 21%; cabinet temperature: 26-30&#160;&#176;C; humidity: 30%-70%; dust entry rate: 2.0-2.5 mL/min; and cabinet dust concentration: 60 &#177; 5 mg/m3. 
	NOTE: Observe the experimental data and equipment status continuously during the experiment. The equipment failure alarm prompted timely processing.
	<ol>
		<li>Expose each animal to silica continuously for 3 h per day, 5 days per week, and allow the animals in the control group to inhale pure air.</li>
	</ol>
	</li>
	<li>On completion of the experiment, close the mixed gas flow control valve, and open the pure gas flow valve. Inject the pure gas continuously into the inhalation chamber. 
	NOTE: In the present study, the pure gas flow (7.0-7.5 m3/h) was injected for at least 20 min until the poisonous gas in the inhalation chamber was completely replaced.
	<ol>
		<li>Close the pure air-flow valve, open the door, take the rats out, and send them back to the pathogen-free room.</li>
	</ol>
	</li>
	<li>Remove the rat rack and the branch pipe components in sequence and place them in the sink for cleaning. After rinsing, close the automatic cleaning valve and open the hatch.
	<ol>
		<li>Wipe the inner wall with a clean cloth, or turn on the pure gas to dry the tank. Finally, carry out the disinfection. After cleaning and disinfecting with 75% ethanol, close the exhaust gate and, as soon as possible, slightly open the door of the inhalation cabin to evaporate the moisture, so that the inside of the inhalation cabin remains dry.</li>
	</ol>
	</li>
	<li>Check the silica concentration in the cabinet with a comprehensive atmospheric sampler following the manufacturer&#39;s instructions (see Table of Materials) twice a week to ensure the stability of the silica concentration during the experiment. Calibrate the atmospheric sampler before sampling.
	<ol>
		<li>Use a digital single-pan analytical balance for gravimetric determination. The calculated silica concentration was 65 mg/m3 (Figure 1 and Table 1). 
		NOTE: Weigh the filter paper before and after the absorption of silica. The concentration of silica was calculated using the following formula12: 
		<img alt="Equation 1" src="/files/ftp_upload/64467/64467eq01.jpg" style="margin: auto;" /> 
		where W2 = weight of the filter paper after sampling, W1 = weight of the filter paper before sampling, and V = volume of the air.</li>
	</ol>
	</li>
</ol>
4. Acquisition and fixation of lung tissues
<ol>
	<li>Euthanize the rats by intraperitoneal injection of pentobarbital (100 mg/kg body weight) and Lidocaine (4&#160;mg/kg body weight). Assess the death by the loss of heartbeat14.</li>
	<li>At the end of the experiment, fix the right lower lung, kidney, liver, spleen, and bone with 4% paraformaldehyde for at least 24 h, embed in paraffin, and cut into 5 &#181;m sections7,15.</li>
</ol>
5. Hematoxylin and eosin (H&#38;E) staining
<ol>
	<li>Deparaffinize the paraffin sections in xylol (see Table of Materials) twice for 10 min each16, and rehydrate in 100% ethanol, 95% ethanol, 90% ethanol, 80% ethanol, 70% ethanol, and distilled water for 3 min each.</li>
	<li>Stain the sections with hematoxylin (see Table of Materials) for 5 min, and then wash the sections with water10.</li>
	<li>Place the sections in 2% hydrochloric alcohol and then in distilled water until the color changes to blue.</li>
	<li>Stain the sections with eosin for 1 min, dehydrate them with 95% ethanol, make them transparent with xylene, seal them with neutral gum, and observe under a light microscope12.</li>
</ol>
6. Immunohistochemical staining
<ol>
	<li>Routinely wash the paraffin sections with water.</li>
	<li>Expose the antigens at high pressure (60 kPa) and high temperature (100 &#176;C) for 80 s and then block with an endogenous peroxidase blocker (3%) for 15 min to eliminate the endogenous peroxidases7.</li>
	<li>Incubate the samples with antibodies directed against CD68 (1:200 dilution-add 4 &#181;L of CD68 to 396 &#181;L of antibody diluent; see Table of Materials) at 4 &#176;C overnight.</li>
	<li>Incubate the samples with a secondary antibody (HRP-conjugated goat anti-mouse IgG polymer; see Table of Materials) at 37 &#176;C for 30 min, and then wash the samples with 1x PBS.</li>
	<li>Visualize the immunoreactivity with 3,3-diaminobenzidine (DAB; see Table of Materials). After applying DAB to the tissue, observe the staining of the tissue under a light microscope10. 
	NOTE: The staining time varied from a few seconds to a few minutes according to the staining time of the tissue. The staining procedure was aborted by placing the sections in water. In this study, the brown staining of the tissue represented the positive expression of CD68. All antibodies were diluted in 1x PBS.</li>
</ol>

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The authors declare no conflict of interest.

As the leading cause of silicosis, silica plays a decisive role in molding. The silica particles inhaled by patients with pneumoconiosis are fresh, free silica particles produced by mechanical cutting. Silica can generate reactive oxygen species either directly on freshly cleaved particle surfaces or indirectly through its effect on the macrophages25. Therefore, the grinding of silica particles is of high importance. In the proposed protocol, silica was ground with agate mortar for more than 90 mi...

Silicosis, which is caused by the inhalation of silica, is the most serious occupational disease in China, accounting for more than 80% of the total number of occupational disease reports every year1. The etiology of silicosis is clear, and it can be prevented and controlled, but no effective treatment method is available2. Many drugs have been proven to be effective in basic studies, but they have imprecise clinical effects3,4. Therefore, the pathological and physiological mechanisms of silicosis still need to be explored.
Many studies have used a one-time infusion of silica into the trachea of rats or mice to investigate the pathogenesis of silicosis5,6. Although these rodent silicotic models could be obtained in a short time7, these methods still had challenges, such as animal trauma and high mortality. Some studies have involved instilling stored silica into the lungs to induce a nonspecific lung reaction, but did not mention silicotic nodules in mice8. Furthermore, away from acute silicosis, chronic exposure to silica in occupational environments induced significantly lower pulmonary inflammation and elevated the levels of anti-apoptotic markers, rather than pro-apoptotic markers, in the lungs9. Therefore, a reliable, reasonable, and repeatable animal model is needed to explore the pathogenesis of silicosis further.
The present study describes a method to mimic the disease process of patients with silicosis through silica inhalation via the whole body, air-delivered particles in an inhalation chamber, which comprised an air-delivered silica generator, a whole-body chamber, and a waste disposal system. This method is simple, easy to operate, and effectively mimics the pathological dynamic evolution process of silicosis. Also, many possible mechanisms and the pathogenesis of silicosis are identified using this method10,11,12. The proposed protocol is anticipated to help further investigations in the related field of silicosis research.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Air detector (compressive atmospheric sampler)</td>
			<td>Qingdao Xuyu Environmental Protection Technology Co. LTD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anatomical table</td>
			<td></td>
			<td></td>
			<td>&#160;No specific brand is recommended.</td>
		</tr>
		<tr>
			<td>Antibody of CD68</td>
			<td>Abcam</td>
			<td>ab201340</td>
			<td></td>
		</tr>
		<tr>
			<td>DAB</td>
			<td>ZSGB-BIO</td>
			<td>ZLI-9018</td>
			<td></td>
		</tr>
		<tr>
			<td>Electric heating air-blowing drier</td>
			<td>Shanghai Yiheng Scientific Instrument Co., LTD</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Electronic balance</td>
			<td>OHRUS</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Embedding machine</td>
			<td>leica</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Exhaust gas discharge device &#160;</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Generator systems&#160;</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gloves (thin laboratory gloves)</td>
			<td>The secco medical</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hematoxylin and eosin</td>
			<td>BaSO Diagnostics Inc.</td>
			<td>BA4025</td>
			<td></td>
		</tr>
		<tr>
			<td>HOPE MED 8050 exposure control apparatus</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Inhalation chamber&#160;</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Injection syringe</td>
			<td></td>
			<td></td>
			<td>&#160;No specific brand is recommended.</td>
		</tr>
		<tr>
			<td>Light microscope&#160;</td>
			<td>olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Object slide</td>
			<td>shitai</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PV-6000 (HRP-conjugated goat anti-mouse IgG polymer)</td>
			<td>Beijing Zhongshan Jinqiao Biotechnology Co. Ltd</td>
			<td>s5631</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon dioxide</td>
			<td>Sigma-Aldrich</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Slicing machine</td>
			<td>leica</td>
			<td>RM2255</td>
			<td></td>
		</tr>
		<tr>
			<td>Waste gas treatment device</td>
			<td>HOPE Industry and Trade Co. Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Wet box</td>
			<td>Cooperative plastic Products Factory</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Xylol</td>
			<td>Tianjin Yongda Chemical Reagent Co., LTD</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

establishing a silicosis rat model via exposure of whole-body to respirable silica

The major cause of silicosis is the inhalation of silica in the occupational environment. Despite some anatomical and physiological differences, rodent models continue to be an essential tool for studying human silicosis. For silicosis, the classic pathological process needs to be inducible via the inhalation of freshly generated quartz particles, which means specifically inducing human occupational disease. This study described a technique to establish and effectively mimic the pathological dynamic evolution process of silicosis. Further, the technique had good repeatability with no surgery involved. The inhalation exposure system was fabricated, validated, and used for toxicology studies on respirable particle inhalation. The critical components were as follows: (1) bulk dry SiO2 powder generator adjusted with an air-flow controller; (2) 0.3 m3 whole-body inhalation exposure chamber accommodating up to 3&#160;adult rats; (3) a monitoring and control system for regulating oxygen concentration, temperature, humidity, and pressure in real-time; and (4) a barrier and waste disposal system for protecting laboratory technicians and the environment. In summary, the present protocol reports the inhalation via the whole body, and the inhalation chamber created a reliable, reasonable, and repeatable rat silicotic model with low mortality, less injury, and more protection.

Using the proposed method, some potential mechanisms and the pathogenesis of silicosis were explored in rats. The schematic of the inhalation chamber is shown in Figure 1. The chamber consisted of an air-delivered silica generator, a whole-body chamber, and a waste disposal system, as previously described17. The pulmonary functions, levels of inflammatory factors in the serum and lung, collagen deposition, and myofibroblast differentiation were reported in the previou...

Watch this Scientific Journal Video about Establishing a Silicosis Rat Model via Exposure of Whole-Body to Respirable Silica at JoVE.com

Establishing a Silicosis Rat Model via Exposure of Whole-Body to Respirable Silica

This study describes a technique to establish a silicosis rat model with the inhalation of silica through the whole body in an inhalation chamber. The rats with silicosis could closely mimic the pathological process of human silicosis in an easy, cost-effective manner with good repeatability.

The major cause of silicosis is the inhalation of silica in the occupational environment. Despite some anatomical and physiological differences, rodent ...

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1.2K Views.  North China University of Science and Technology. This study describes a technique to establish a silicosis rat model with the inhalation of silica through the whole body in an inhalation chamber. The rats with silicosis could closely mimic the pathological process of human silicosis in an easy, cost-effective manner with good repeatability.

Video: Establishing a Silicosis Rat Model via Exposure of Whole-Body to Respirable Silica

Assessing Teratogenic Changes in a Zebrafish Model of Fetal Alcohol Exposure

Fetal alcohol syndrome (FAS) is a severe manifestation of embryonic exposure to ethanol. It presents with characteristic defects to the face and organs, including mental retardation due to disordered and damaged brain development. Fetal alcohol spectrum disorder (FASD) is a term used to cover a continuum of birth defects that occur due to maternal alcohol consumption, and occurs in approximately 4% of children born in the United States. With 50% of child-bearing age women reporting consumption of alcohol, and half of all pregnancies being unplanned, unintentional exposure is a continuing issue2. In order to best understand the damage produced by ethanol, plus produce a model with which to test potential interventions, we developed a model of developmental ethanol exposure using the zebrafish embryo. Zebrafish are ideal for this kind of teratogen study3-8. Each pair lays hundreds of eggs, which can then be collected without harming the adult fish. The zebrafish embryo is transparent and can be readily imaged with any number of stains. Analysis of these embryos after exposure to ethanol at different doses and times of duration and application shows that the gross developmental defects produced by ethanol are consistent with the human birth defect. Described here are the basic techniques used to study and manipulate the zebrafish FAS model.

In order to understand the molecular mechanisms of the ethanol-induced developmental damage, we have developed a zebrafish model of ethanol exposure and are exploring the physical, cellular, and genetic alterations that occur after ethanol exposure1. We then seek to find potential interventions and rapidly test them in this animal model.

Fetal alcohol syndrome (FAS) is a severe manifestation of embryonic exposure to ethanol. It presents with characteristic defects to the face and organs, ...

Protocol for Long Duration Whole Body Hyperthermia in Mice

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol.

This paper describes a protocol for whole body hyperthermia in mice that can stimulate fever like conditions up to 12-24 hr.

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body ...

Rat Model of Blood-brain Barrier Disruption to Allow Targeted Neurovascular Therapeutics

Endothelial cells with tight junctions along with the basement membrane and astrocyte end feet surround cerebral blood vessels to form the blood-brain barrier1. The barrier selectively excludes molecules from crossing between the blood and the brain based upon their size and charge. This function can impede the delivery of therapeutics for neurological disorders. A number of chemotherapeutic drugs, for example, will not effectively cross the blood-brain barrier to reach tumor cells2. Thus, improving the delivery of drugs across the blood-brain barrier is an area of interest.
The most prevalent methods for enhancing the delivery of drugs to the brain are direct cerebral infusion and blood-brain barrier disruption3. Direct intracerebral infusion guarantees that therapies reach the brain; however, this method has a limited ability to disperse the drug4. Blood-brain barrier disruption (BBBD) allows drugs to flow directly from the circulatory system into the brain and thus more effectively reach dispersed tumor cells. Three methods of barrier disruption include osmotic barrier disruption, pharmacological barrier disruption, and focused ultrasound with microbubbles. Osmotic disruption, pioneered by Neuwelt, uses a hypertonic solution of 25% mannitol that dehydrates the cells of the blood-brain barrier causing them to shrink and disrupt their tight junctions. Barrier disruption can also be accomplished pharmacologically with vasoactive compounds such as histamine5 and bradykinin6. This method, however, is selective primarily for the brain-tumor barrier7. Additionally, RMP-7, an analog of the peptide bradykinin, was found to be inferior when compared head-to-head with osmotic BBBD with 25% mannitol8. Another method, focused ultrasound (FUS) in conjunction with microbubble ultrasound contrast agents, has also been shown to reversibly open the blood-brain barrier9. In comparison to FUS, though, 25% mannitol has a longer history of safety in human patients that makes it a proven tool for translational research10-12.
In order to accomplish BBBD, mannitol must be delivered at a high rate directly into the brain's arterial circulation. In humans, an endovascular catheter is guided to the brain where rapid, direct flow can be accomplished. This protocol models human BBBD as closely as possible. Following a cut-down to the bifurcation of the common carotid artery, a catheter is inserted retrograde into the ECA and used to deliver mannitol directly into the internal carotid artery (ICA) circulation. Propofol and N2O anesthesia are used for their ability to maximize the effectiveness of barrier disruption13. If executed properly, this procedure has the ability to safely, effectively, and reversibly open the blood-brain barrier and improve the delivery of drugs that do not ordinarily reach the brain 8,13,14.

Blood-brain barrier disruption aids the delivery of certain drugs to the brain. Mannitol delivered intra-arterially shrinks cells surrounding blood vessels in order to physically disrupt the barrier.

Endothelial cells with tight junctions along with the basement membrane and astrocyte end feet surround cerebral blood vessels to form the blood-brain ...

Construction and Evaluation of a Murine Calvarial Osteolysis Model by Exposure to CoCrMo Particles in Aseptic Loosening

Wear particle-induced osteolysis is a major cause of aseptic loosening in arthroplasty failure, but the underlying mechanism remains unclear. Due to long follow-ups necessary for detection and sporadic occurrence, it is challenging to assess the pathogenesis ofparticle-induced osteolysis in clinical cases. Hence, optimal animal models are required for further studies. The murine model of calvarial osteolysis established by exposure to CoCrMo particles is an effective and valid tool for assessing the interactions between particles and various cells in aseptic loosening. In this model, CoCrMo particles were first obtained by high-vacuum three-electrode direct current and resuspended in phosphate-buffered saline at a concentration of 50 mg/mL. Then, 50 &#181;L of the resulting suspension was applied to the middle of the murine calvaria after separation of the cranial periosteum by sharp dissection. After two weeks, the mice were sacrificed, and calvaria specimens were harvested; qualitative and quantitative evaluations were performed by hematoxylin and eosin staining and micro computed tomography. The strengths of this model include procedure simplicity, quantitative evaluation of bone loss, rapidity of osteolysis development, potential use transgenic or knockout models, and a relatively low cost. However, this model cannot to be used to assess the mechanical force and chronic effects of particles in aseptic loosening. Murine calvarial osteolysis model generated by exposure to CoCrMo particles is an ideal tool for assessing the interactions between wear particles and various cells, e.g., macrophages, fibroblasts, osteoblasts and osteoclasts, in aseptic loosening.

This manuscript describes a murine calvarial osteolysis model by exposure to CoCrMo particles, which constitutes an ideal animal model for assessing the interactions between wear particles and various cells in aseptic loosening.

Wear particle-induced osteolysis is a major cause of aseptic loosening in arthroplasty failure, but the underlying mechanism remains unclear. Due to long ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

Whole Body and Regional Quantification of Active Human Brown Adipose Tissue Using 18F-FDG PET/CT

In endothermic animals, brown adipose tissue (BAT) is activated to produce heat for defending body temperature in response to cold. BAT&#39;s ability to expend energy has made it a potential target for novel therapies to ameliorate obesity and associated metabolic disorders in humans. Though this tissue has been well studied in small animals, BAT&#39;s thermogenic capacity in humans remains largely unknown due to the difficulties of measuring its volume, activity, and distribution. Identifying and quantifying active human BAT is commonly performed using 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography and computed tomography (PET/CT) scans following cold-exposure or pharmacological activation. Here we describe a detailed image-analysis approach to quantify total-body human BAT from 18F-FDG PET/CT scans using an open-source software. We demonstrate the drawing of user-specified regions of interest to identify metabolically active adipose tissue while avoiding common non-BAT tissues, to measure BAT volume and activity, and to further characterize its anatomical distribution. Although this rigorous approach is time-consuming, we believe it will ultimately provide a foundation to develop future automated BAT quantification algorithms.

Whole Body and Regional Quantification of Active Human Brown Adipose Tissue Using 18F-FDG PET/CT

Using free, open-source software, we have developed an analytical approach to quantify total and regional brown adipose tissue (BAT) volume and metabolic activity of BAT using 18F-FDG PET/CT.

In endothermic animals, brown adipose tissue (BAT) is activated to produce heat for defending body temperature in response to cold. BAT&#39;s ability to ...

A Murine Model of Fetal Exposure to Maternal Inflammation to Study the Effects of Acute Chorioamnionitis on Newborn Intestinal Development

Chorioamnionitis is a common precipitant of preterm birth and is associated with many of the morbidities of prematurity, including necrotizing enterocolitis (NEC). However, a mechanistic link between these two conditions remains yet to be discovered. We have adopted a murine model of chorioamnionitis involving lipopolysaccharide (LPS)-induced fetal exposure to maternal inflammation (FEMI). This model of FEMI induces a sterile maternal, placental, and fetal inflammatory cascade, which is also present in many cases of clinical chorioamnionitis. Although models exist that utilize live bacteria and more accurately mimic the pathophysiology of an ascending infection resulting in chorioamnionitis, these methods may cause indirect effects on development of the immature intestinal tract and the associated developing microbiome. Using this protocol, we have demonstrated that LPS-induced FEMI results in a dose-dependent increase in pregnancy loss and preterm birth, as well as disruption of normal intestinal development in offspring. Further, we have demonstrated that FEMI significantly increases intestinal injury and serum cytokines in offspring, while simultaneously decreasing goblet and Paneth cells, both of which provide a first line of innate immunity against intestinal inflammation. Although a similar model of LPS-induced FEMI has been used to model the association between chorioamnionitis and subsequent abnormalities of the central nervous system, to our knowledge, this protocol is the first to attempt to elucidate a mechanistic link between chorioamnionitis and later perturbations in intestinal development as a potential link between chorioamnionitis and NEC.

We developed a model of chorioamnionitis to simulate fetal exposure to maternal inflammation (FEMI) without complications of live organisms to examine the effects of FEMI on development of the offspring&#8217;s intestinal tract. This allows for study of mechanistic causes for development of intestinal injury following chorioamnionitis.

Chorioamnionitis is a common precipitant of preterm birth and is associated with many of the morbidities of prematurity, including necrotizing ...

Acupuncture in a Rat Model of Asthma

A high platform can fix rats without restriction and completely expose the acupoints on the back during acupuncture manipulation. This article describes methods for the fabrication of the high platform, establishes a rat model of asthma and measures changes in respiratory function using a noninvasive and real-time whole-body plethysmography (WBP) system.

A high platform can fix rats without restriction and completely expose the acupoints on the back during acupuncture manipulation. This article describes ...

Assessing Whole-Body Lipid-Handling Capacity in Mice

Assessing lipid metabolism is a cornerstone of evaluating metabolic function, and it is considered essential for in vivo metabolism studies. Lipids are a class of many different molecules with many pathways involved in their synthesis and metabolism. A starting point for evaluating lipid hemostasis for nutrition and obesity research is needed. This paper describes three easy and accessible methods that require little expertise or practice to master, and that can be adapted by most labs to screen for lipid-metabolism abnormalities in mice. These methods are (1) measuring several fasting serum lipid molecules using commercial kits (2) assaying for dietary lipid-handling capability through an oral intralipid tolerance test, and (3) evaluating the response to a pharmaceutical compound, CL 316,243, in mice. Together, these methods will provide a high-level overview of lipid handling capability in mice.

This paper provides three easy and accessible assays for assessing lipid metabolism in mice.

Assessing lipid metabolism is a cornerstone of evaluating metabolic function, and it is considered essential for in vivo metabolism studies. Lipids are a ...

A Silicosis Mouse Model Established by Repeated Inhalation of Crystalline Silica Dust

Silicosis can be caused by exposure to respiratory crystalline silica dust (CSD) in an industrial environment. The pathophysiology, screening, and treatment of silicosis in humans have all been extensively studied using the mouse silicosis model. By repeatedly making mice inhale CSD into their lungs, the mice can mimic the clinical symptoms of human silicosis. This methodology is practical and efficient in terms of time and output and does not cause mechanical injury to the upper respiratory tract due to surgery. Furthermore, this model can successfully mimic acute/chronic transformation process of silicosis. The main procedures were as follows. The sterilized 1-5 &#181;m CSD powder was fully ground, suspended in saline, and dispersed in an ultrasonic water bath for 30 min. Mice under isoflurane-induced anesthesia switched from shallow rapid breathing to deep, slow aspiration for approximately 2 s. The mouse was placed in the palm of a hand, and the thumb tip gently touched the lip edge of the mouse's jaw to straighten the airway. After each exhalation, the mice breathed in the silica suspension drop by drop through one nostril, completing the process within 4-8 s. After the mice's breathing had stabilized, their chest was stroked and caressed to prevent the inhaled CSD from being coughed up. The mice were then returned to the cage. In conclusion, this model can quantify CSD along the typical physiological passage of tiny particles into the lung, from the upper respiratory tract to the terminal bronchioles and alveoli. It can also replicate the recurrent exposure of employees due to work. The model can be performed by one person and does not need expensive equipment. It conveniently and effectively simulates the disease features of human silicosis with high repeatability.

This protocol describes a method for establishing a mouse model of silicosis through repeated exposure to silica suspensions via a nasal drip. This model can efficiently, conveniently, and flexibly mimic the pathological process of human silicosis with high repeatability and economy.