Name: development of a direct pulp-capping model for the evaluation of pulpal wound healing and reparative dentin formation in mice
Uploaded: 2017-01-12T12:30:00
Description: Watch this Scientific Journal Video about Development of a Direct Pulp-capping Model for the Evaluation of Pulpal Wound Healing and Reparative Dentin Formation in Mice at JoVE.com

This study was supported by R01DE023348 (RHK) from NIDCR/NIH and the Faculty Research Grant (RHK) from the Council on Research of the Academic Senate of the Los Angeles Division of the University of California.

Mice were purchased from Jackson Laboratory and kept in a pathogen-free vivarium in the UCLA Division of Laboratory Animal Medicine (DLAM). The experiments were performed according to the approved institutional guidelines from the Chancellor&#39;s Animal Research Committee&#160;(ARC#2016-037).
1. Mouse Anesthetization
<ol>
	<li>Use eight-week-old female C57/BL6 mice (n = 3).</li>
	<li>Anesthetize the mice using ketamine (80-120 mg/kg of mouse weight)/xylazine (5 mg/kg of mouse weight) solutions and administer in...

<ol>
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Currently, there are several different experimental models available to validate the in vivo effects of dental materials, scaffolds, or growth factors on odontogenic differentiation of dental pulp stem cells (DPSCs)13. These models include ectopic autologous transplantation of DPSCs into an organ, such as the renal capsule, or subcutaneous transplantation of DPSCs into immunocompromised mice with scaffolds14,15. However, these methods are limited in that their odontogenic effect on DPSCs is...

Dental caries are one of the most prevalent oral diseases and the leading cause of surgical interventions to dentitions in almost all individuals1,2. The prognosis of surgical interventions and restorations of a tooth largely depends upon proper pulpal response and successful wound healing. Indeed, dental caries that penetrate deeply through the enamel and dentin frequently lead to the exposure of the underlying pulp tissue that is often "capped" with dental materials, such as calcium hydroxide (Ca(OH)2) or hydraulic calcium-silicate cements (HCSCs), including mineral trioxide aggregates (MTA). The ultimate goal of such a pulp-capping procedure is to expedite pulpal wound healing by regenerating reparative dentin, a physical barrier that functions as a "biological seal" to protect the underlying pulp tissue and to increase the life expectancy of the tooth and the overall oral health. However, the underlying mechanism of pulpal wound healing and reparative dentin formation is not fully understood.
To better understand the mechanisms of pulpal wound healing and reparative dentin formation in vivo, several animals were previously used, including monkeys, dogs, and pigs3-5. Among them, rats are frequently used because they are relatively smaller in sizes compared to the other animals, but their teeth are large enough to perform direct pulp capping without any technical difficulties6-10. These animal models are ideal alternatives to human studies for examining pulpal responses and reparative dentin formation. However, their utilization is limited to observational studies at the cellular level, and they scarcely provide mechanistic insights during reparative dentin formation at the molecular level.
Recent technical advances in genetic engineering provided invaluable and indispensable research tools-mice that harbor a gene that is either overexpressed or deleted-that are instrumental to studying molecular mechanisms of human diseases in vivo. The numbers of different strains of transgenic or knockout mice that are strategically inducible in a cell-specific manner are continually growing in the scientific community. Therefore, examining pulpal wound healing and reparative dentin regeneration in these mice would greatly help to expedite our understanding of these processes at the molecular level. However, the use of mice is significantly dampened, as performing a pulp-capping procedure on a mouse tooth is technically challenging due to its miniature size. Here, we present our reproducible method of performing direct pulp capping in mice for the evaluation of pulpal wound healing and reparative dentin formation in vivo.

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		<tr height="21">
			<td height="21" style="height:21px;width:164px;">BM-LED stereo microscope</td>
			<td style="width:164px;">MEIJI Techno</td>
			<td style="width:140px;"></td>
			<td style="width:173px;">Microscope&#160;</td>
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		<tr height="21">
			<td height="21" style="height:21px;">Optima MCX-LED&#160;</td>
			<td>Bien Air Dental</td>
			<td>1700588-001</td>
			<td>Electic motor engine</td>
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			<td height="21" style="height:21px;">isoflurane</td>
			<td>Henry schein animal health</td>
			<td>NDC 11695-0500-2</td>
			<td></td>
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			<td height="21" style="height:21px;">1/4 round bur</td>
			<td>Brasseler</td>
			<td>001092T0</td>
			<td></td>
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			<td height="21" style="height:21px;">Endodontic K-file</td>
			<td>Roydent</td>
			<td>98947</td>
			<td></td>
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			<td height="21" style="height:21px;">ProRoot MTA</td>
			<td>Dentsply</td>
			<td>PROROOT5W</td>
			<td>MTA</td>
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			<td height="21" style="height:21px;">Paper point</td>
			<td>Henry schein</td>
			<td>100-3941</td>
			<td></td>
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			<td height="21" style="height:21px;">Ultra-Etch</td>
			<td>Ultradent product Inc.</td>
			<td></td>
			<td>Phosphoric acid etchant</td>
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		<tr height="21">
			<td height="21" style="height:21px;">OptiBond SoloPlus</td>
			<td>Kerr</td>
			<td>29669</td>
			<td>Adhesives</td>
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		<tr height="21">
			<td height="21" style="height:21px;">Coltolux LED</td>
			<td>Coltene/whaledent Inc.</td>
			<td>C7970100115</td>
			<td>Curing light unit</td>
		</tr>
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			<td height="21" style="height:21px;">Characterization tint</td>
			<td>Bisco</td>
			<td>T-14012</td>
			<td>Flowable composite</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Skyscan</td>
			<td>Breuker</td>
			<td>1275</td>
			<td>uCT scanner</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microm</td>
			<td>Thermo</td>
			<td>HM355S</td>
			<td>Microtome</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hematoxyline-1</td>
			<td>Thermo Scientific</td>
			<td>7221</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Eosin-Y</td>
			<td>Thermo Scientific</td>
			<td>7111</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cytoseal 60</td>
			<td>Thermo Scientific</td>
			<td>8310-16</td>
			<td>Mounting solution</td>
		</tr>
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development of a direct pulp-capping model for the evaluation of pulpal wound healing and reparative dentin formation in mice

Dental pulp is a vital organ of a tooth fully protected by enamel and dentin. When the pulp is exposed due to cariogenic or iatrogenic injuries, it is often capped with biocompatible materials in order to expedite pulpal wound healing. The ultimate goal is to regenerate reparative dentin, a physical barrier that functions as a "biological seal" and protects the underlying pulp tissue. Although this direct pulp-capping procedure has long been used in dentistry, the underlying molecular mechanism of pulpal wound healing and reparative dentin formation is still poorly understood. To induce reparative dentin, pulp capping has been performed experimentally in large animals, but less so in mice, presumably due to their small sizes and the ensuing technical difficulties. Here, we present a detailed, step-by-step method of performing a pulp-capping procedure in mice, including the preparation of a Class-I-like cavity, the placement of pulp-capping materials, and the restoration procedure using dental composite. Our pulp-capping mouse model will be instrumental in investigating the fundamental molecular mechanisms of pulpal wound healing in the context of reparative dentin in vivo by enabling the use of transgenic or knockout mice that are widely available in the research community.

Here, we showed the step-by-step procedures to perform pulp capping on mice teeth. One of the key aspects of pulp capping in mice is to have the appropriate apparatus. In this regard, having the microscope with a 10X power magnification is essential (Figure 1A). To create a Class-I-like preparation in the tooth, we used a &#188;-round burr in an electric high speed handpiece at 200,000 rpm (Figure 1B). Alternatively, any other engines, including those tha...

Watch this Scientific Journal Video about Development of a Direct Pulp-capping Model for the Evaluation of Pulpal Wound Healing and Reparative Dentin Formation in Mice at JoVE.com

Development of a Direct Pulp-capping Model for the Evaluation of Pulpal Wound Healing and Reparative Dentin Formation in Mice

We describe a step-by-step method of performing direct pulp capping on mice teeth for the evaluation of pulpal wound healing and reparative dentin formation in vivo.

Dental pulp is a vital organ of a tooth fully protected by enamel and dentin. When the pulp is exposed due to cariogenic or iatrogenic injuries, it is ...

The overall goal of this protocol is to present the direct pulp-capping procedure in mice. This method can help you answer key questions in pulp biology, such as, how pulp heals, or how reparative dentin forms, when you place trapped pulp-capping materials on the exposed pulp. The main advantage of this technique is that the actual direct pulp-capping procedure performed in humans can also be done in mice, in exactly the same manner.The implications of this technique extends towards improving material properties to save tooths that is otherwise doomed to be more invasive treatments, such as root canal therapy. After properly anesthetizing the mouse for the procedure, position the mouth holder in its mouth, and secure the other end to the table such that the head is facing upward. Using good lighting and a stereoscope, observe the first maxillary molar.Then, using the quarter-round bur in a high speed handpiece at 200, 000 rpm, remove the central region of the tooth's enamel until the pulp is visible through the transparent dentin. Be careful to not penetrate into the pulp. Next, using a no.15 endodontic k-file, perforate through the dentin and expose the pulp. Do not push any debris into the pulp;this can be avoided by rotating the k-file quarterly, and then pulling the k-file out. Now, prepare the MTA, and using the explorer, deliver the MTA, then pack it into the exposed region using the back side of the paper point and gentle tapping.Next, using a syringe loaded with 35%phosphoric acid etchant, cover the tooth with the etchant, avoiding the gingival tissues, and let the etchant work for 15 seconds. After 15 seconds, suck the etchant off the tooth, and use a water-moistened cotton applicator to wipe off any remaining etchant. Suck and wipe until all the etchant is removed.Follow by applying the dental adhesives using the backside of the paper point. Make the adhesive layer thin by blowing it with compressed air for a few seconds. Then cure the adhesive for 30 seconds with the appropriate light.Now, place small amounts of composite onto the tooth using the tip of the explorer to flow the composite into the tooth grooves. Once applied, cure the composite for 30 seconds. After euthanizing the mouse and removing the entire maxilla, place the jaw into 4%paraformaldehyde in PBS at pH 7.4.Keep the tissue at 4 degrees Celsius overnight, and on the following morning, transfer it to 70%ethanol for storage until it can be processed. To take a micro CT scan of the maxilla, first secure it in gauze soaked with 70%ethanol, then pack it into a 15 milliliter cell culture tube. Then mount the tube onto the micro CT scanning stage.Next, set the x-ray source to deliver a 145 microamp current with 55 peak kilovolts for 200 milliseconds. Using a 0.5 millimeter aluminum filter, acquire images with 20 micron resolution. After the scans are completed, start decalcifying the maxilla with 5%EDTA and 4%sucrose in PBS, at a pH of 7.4.Let this reaction go for two weeks at 4 degrees Celsius. After embedding the maxilla, make five micron thick slices. The pulp-capping areas usually coincide with the distal palatal root, which can be used as a landmark.Determine the precise area of interest by examining the histology under the light microscope, and comparing the results to the micro CT scans. For H&E staining, remove the paraffin, and rehydrate the slides with two baths in xylene for a few minutes each. Then pass them through a series of serially diluted ethanol.Each bath should be applied for just one minute. Follow the rehydration with a rinse. And then apply the hemotoxylin solution for two and a half minutes.Remove the dye with a rinse, and then put the slides in 95%ethanol for one minute. Next, stain the slides with eosin solution for one minute, and then rinse them off. Reverse the hydration steps to dehydrate the stained tissues, starting with ethanol.Then, treat them with xylene. The slides can then be mounted and imaged. Using the described procedures, pulp-capping was performed on 8-week-old mice.Six weeks later, their maxilla were harvested and examined. Curiously, H&E staining revealed dentin formation throughout the pulp chamber and the root canals. Comparatively, the uncapped molar did not show the same dentin formation.In the capped molar, there were characteristics of both dentin-like and bone-like formation, as both dentinal tubules, and osteocytes were found in the reparative dentin, suggesting that injured pulp may be mineralized by both residing odontoblasts and immigrated osteoblasts. Use of DMP1 immunohistochemical staining further confirmed increased activities of cells forming reparative dentin. Just like real dental clinical practices, having an assistant is extremely helpful.For example, with an assistant, this technique can be done in just ten minutes, once mastered. Importantly, when you're exposing the pulp, remember to use endofile, not the bur. And when you're handing the MTA, be careful.Don't forget that working with fixatives like paraformaldehyde can be extremely hazardous. Precautions such as wearing personal protective equipment should always be taken.

development-direct-pulp-capping-model-for-evaluation-pulpal-wound

Research

JoVE Journal

Medicine

Murine Model of Wound Healing

Wound healing and repair are the most complex biological processes that occur in human life. After injury, multiple biological pathways become activated. Impaired wound healing, which occurs in diabetic patients for example, can lead to severe unfavorable outcomes such as amputation. There is, therefore, an increasing impetus to develop novel agents that promote wound repair. The testing of these has been limited to large animal models such as swine, which are often impractical. Mice represent the ideal preclinical model, as they are economical and amenable to genetic manipulation, which allows for mechanistic investigation. However, wound healing in a mouse is fundamentally different to that of humans as it primarily occurs via contraction. Our murine model overcomes this by incorporating a splint around the wound. By splinting the wound, the repair process is then dependent on epithelialization, cellular proliferation and angiogenesis, which closely mirror the biological processes of human wound healing. Whilst requiring consistency and care, this murine model does not involve complicated surgical techniques and allows for the robust testing of promising agents that may, for example, promote angiogenesis or inhibit inflammation. Furthermore, each mouse acts as its own control as two wounds are prepared, enabling the application of both the test compound and the vehicle control on the same animal. In conclusion, we demonstrate a practical, easy-to-learn, and robust model of wound healing, which is comparable to that of humans.

A murine model of cutaneous wound healing that can be used to assess therapeutic compounds in physiological and pathophysiological settings.

Wound healing and repair are the most complex biological processes that occur in human life. After injury, multiple biological pathways become activated. ...

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation

Mouse models are widely used to study pathogenesis of human diseases and to evaluate diagnostic procedures as well as therapeutic interventions preclinically. However, valid assessment of pathological alterations often requires histological analysis, and when performed ex vivo, necessitates death of the animal. Therefore in conventional experimental settings, intra-individual follow-up examinations are rarely possible. Thus, development of murine endoscopy in live mice enables investigators for the first time to both directly visualize the gastrointestinal mucosa and also repeat the procedure to monitor for alterations. Numerous applications for in vivo murine endoscopy exist, including studying intestinal inflammation or wound healing, obtaining mucosal biopsies repeatedly, and to locally administer diagnostic or therapeutic agents using miniature injection catheters. Most recently, molecular imaging has extended diagnostic imaging modalities allowing specific detection of distinct target molecules using specific photoprobes. In conclusion, murine endoscopy has emerged as a novel cutting-edge technology for diagnostic experimental in vivo imaging and may significantly impact on preclinical research in various fields.

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation

Small animal imaging techniques allow serial diagnostic examinations and therapeutic interventions in vivo. Recently, the scope of applications has significantly widened and currently includes assessment of colonic tumor development, wound healing and monitoring of inflammation. This protocol illustrates these diverse potential applications of murine endoscopy.

Mouse models are widely used to study pathogenesis of human diseases and to evaluate diagnostic procedures as well as therapeutic interventions ...

Creation and Transplantation of an Adipose-derived Stem Cell (ASC) Sheet in a Diabetic Wound-healing Model

Artificial skin has achieved considerable therapeutic results in clinical practice. However, artificial skin treatments for wounds in diabetic patients with impeded blood flow or with large wounds might be prolonged. Cell-based therapies have appeared as a new technique for the treatment of diabetic ulcers, and cell-sheet engineering has improved the efficacy of cell transplantation. A number of reports have suggested that adipose-derived stem cells (ASCs), a type of mesenchymal stromal cell (MSC), exhibit therapeutic potential due to their relative abundance in adipose tissue and their accessibility for collection when compared to MSCs from other tissues. Therefore, ASCs appear to be a good source of stem cells for therapeutic use. In this study, ASC sheets from the epididymal adipose fat of normal Lewis rats were successfully created using temperature-responsive culture dishes and normal culture medium containing ascorbic acid. The ASC sheets were transplanted into Zucker diabetic fatty (ZDF) rats, a rat model of type 2 diabetes and obesity, that exhibit diminished wound healing. A wound was created on the posterior cranial surface, ASC sheets were transplanted into the wound, and a bilayer artificial skin was used to cover the sheets. ZDF rats that received ASC sheets had better wound healing than ZDF rats without the transplantation of ASC sheets. This approach was limited because ASC sheets are sensitive to dry conditions, requiring the maintenance of a moist wound environment. Therefore, artificial skin was used to cover the ASC sheet to prevent drying. The allogenic transplantation of ASC sheets in combination with artificial skin might also be applicable to other intractable ulcers or burns, such as those observed with peripheral arterial disease and collagen disease, and might be administered to patients who are undernourished or are using steroids. Thus, this treatment might be the first step towards improving the therapeutic options for diabetic wound healing.

Creation and Transplantation of an Adipose-derived Stem Cell ASC Sheet in a Diabetic Wound-healing Model

Adipose-derived stem cells (ASCs) are easily isolated and harvested from the fat of normal rats. ASC sheets can be created using cell-sheet engineering and can be transplanted into Zucker diabetic fatty rats exhibiting full-thickness skin defects with exposed bone and then covered with a bilayer of artificial skin.

Artificial skin has achieved considerable therapeutic results in clinical practice. However, artificial skin treatments for wounds in diabetic patients ...

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The amount of the different tissues in the callus provides important information on the fracture healing progress. Available in vivo techniques to longitudinally monitor the callus tissue development in preclinical fracture-healing studies using small animals include digital radiography and &#181;CT imaging. However, both techniques are only able to distinguish between mineralized and non-mineralized tissue. Consequently, it is impossible to discriminate cartilage from fibrous tissue. In contrast, magnetic resonance imaging (MRI) visualizes anatomical structures based on their water content and might therefore be able to noninvasively identify soft tissue and cartilage in the fracture callus. Here, we report the use of an MRI-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice. The experiments demonstrated that the fixator and a custom-made mounting device allow repetitive MRI scans, thus enabling longitudinal analysis of fracture-callus tissue development.

In Vivo Evaluation of Fracture Callus Development During Bone Healing in Mice Using an MRI-compatible Osteosynthesis Device for the Mouse Femur

The evaluation of tissue development in the fracture callus during endochondral bone healing is essential to monitor the healing process. Here, we report the use of a magnetic resonance imaging (MRI)-compatible external fixator for the mouse femur to allow MRI scans during bone regeneration in mice.

Endochondral fracture healing is a complex process involving the development of fibrous, cartilaginous, and osseous tissue in the fracture callus. The ...

Microscopy Based Methods for the Assessment of Epithelial Cell Migration During In Vitro Wound Healing

Cell migration is a mandatory aspect for wound healing. Creating artificial wounds on research animal models often results in costly and complicated experimental procedures, while potentially lacking in precision. In vitro culture of epithelial cell lines provides a suitable platform for researching the cell migratory behavior in wound healing and the impact of treatments on these cells. The physiology of epithelial cells is often studied in non-confluent conditions; however, this approach may not resemble natural wound healing conditions. Disrupting the epithelium integrity by mechanical means generates a realistic model, but may impede the application of molecular techniques. Consequently, microscopy based techniques are optimal for studying epithelial cell migration in vitro. Here we detail two specific methods, the artificial wound scratch assay and the artificial migration front assay, that can obtain quantitative and qualitative data, respectively, on the migratory performance of epithelial cells.

Microscopy Based Methods for the Assessment of Epithelial Cell Migration During  In Vitro Wound Healing

This manuscript describes how incision-like lesions made on cultured epithelial cell monolayers conveniently model wound healing in vitro, allowing for imaging by confocal or laser scanning microscopy, and which can provide high-quality quantitative and qualitative data for studying both cell behavior and the mechanisms involved in migration.

Cell migration is a mandatory aspect for wound healing. Creating artificial wounds on research animal models often results in costly and complicated ...

A Minimally Invasive Model to Analyze Endochondral Fracture Healing in Mice Under Standardized Biomechanical Conditions

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an increased use of mouse models in orthopedic research was noted, most probably because mouse models offer a large number of genetically-modified strains and special antibodies for the analysis of molecular mechanisms of fracture healing. To control the biomechanical conditions, well-characterized osteosynthesis techniques are mandatory, also in mice. Here, we report on the design and use of a closed bone healing model to stabilize femur fractures in mice. The intramedullary screw, made of medical-grade stainless steel, provides through fracture compression an axial and rotational stability compared to the mostly used simple intramedullary pins, which show a complete lack of axial and rotational stability. The stability achieved by the intramedullary screw allows the analysis of endochondral healing. A large amount of callus tissue, received after stabilization with the screw, offers ideal conditions to harvest tissue for biochemical and molecular analyses. A further advantage of the use of the screw is the fact that the screw can be inserted into the femur with a minimally invasive technique without inducing damage to the soft tissue. In conclusion, the screw is a unique implant that can ideally be used in closed fracture healing models offering standardized biomechanical conditions.

This protocol describes a minimally invasive osteosynthesis technique using an intramedullary screw for standardized stabilization of femur fractures, which can be used to analyze endochondral bone healing in mice.

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an ...

Corneal Epithelial Abrasion with Ocular Burr As a Model for Cornea Wound Healing

The murine cornea provides an excellent model to study wound healing. The cornea is the outermost layer of the eye, and thus is the first defense to injury. In fact, the most common type of eye injury found in clinic is a corneal abrasion. Here, we utilize an ocular burr to induce an abrasion resulting in removal of the corneal epithelium in vivo on anesthetized mice. This method allows for targeted and reproducible epithelial disruption, leaving other areas intact. In addition, we describe the visualization of the abraded epithelium with fluorescein staining and provide concrete advice on how to visualize the abraded cornea. Then, we follow the timeline of wound healing 0, 18, and 72 h after abrasion, until the wound is re-epithelialized. The epithelial abrasion model of corneal injury is ideal for studies on epithelial cell proliferation, migration and re-epithelialization of the corneal layers. However, this method is not optimal to study stromal activation during wound healing, because the ocular burr does not penetrate to the stromal cell layers. This method is also suitable for clinical applications, for example, pre-clinical test of drug effectiveness.

This protocol describes a method to inflict an abrasion to the ocular surface of the mouse, and to follow the wound healing process thereafter. The protocol takes advantage of an ocular burr to partially remove the surface epithelium of the eye in anaesthetized mice.

The murine cornea provides an excellent model to study wound healing. The cornea is the outermost layer of the eye, and thus is the first defense to ...

The Generation of Closed Femoral Fractures in Mice: A Model to Study Bone Healing

Bone fractures impose a tremendous socio-economic burden on patients, in addition to significantly affecting their quality of life. Therapeutic strategies that promote efficient bone healing are non-existent and in high demand. Effective and reproducible animal models of fractures healing are needed to understand the complex biological processes associated with bone regeneration. Many animal models of fracture healing have been generated over the years; however, murine fracture models have recently emerged as powerful tools to study bone healing. A variety of open and closed models have been developed, but the closed femoral fracture model stands out as a simple method for generating rapid and reproducible results in a physiologically relevant manner. The goal of this surgical protocol is to generate unilateral closed femoral fractures in mice and facilitate a post-fracture stabilization of the femur by inserting an intramedullary steel rod. Although devices such as a nail or a screw offer greater axial and rotational stability, the use of an intramedullary rod provides a sufficient stabilization for consistent healing outcomes without producing new defects in the bone tissue or damaging nearby soft tissue. Radiographic imaging is used to monitor the progression of callus formation, bony union, and subsequent remodeling of the bony callus. Bone healing outcomes are typically associated with the strength of the healed bone and measured with torsional testing. Still, understanding the early cellular and molecular events associated with fracture repair is critical in the study of bone tissue regeneration. The closed femoral fracture model in mice with intramedullary fixation serves as an attractive platform to study bone fracture healing and evaluate therapeutic strategies to accelerate healing.

The murine closed femoral fracture model is a powerful platform to study fracture healing and novel therapeutic strategies to accelerate bone regeneration. The goal of this surgical protocol is to generate unilateral closed femoral fractures in mice using an intramedullary steel rod to stabilize the femur.

Bone fractures impose a tremendous socio-economic burden on patients, in addition to significantly affecting their quality of life. Therapeutic strategies ...

Ex Vivo Corneal Organ Culture Model for Wound Healing Studies

The cornea has been used extensively as a model system to study wound healing. The ability to generate and utilize primary mammalian cells in two dimensional (2D) and three dimensional (3D) culture has generated a wealth of information not only about corneal biology but also about wound healing, myofibroblast biology, and scarring in general. The goal of the protocol is an assay system for quantifying myofibroblast development, which characterizes scarring. We demonstrate a corneal organ culture ex vivo model using pig eyes. In this anterior keratectomy wound, corneas still in the globe are wounded with a circular blade called a trephine. A plug of approximately 1/3 of the anterior cornea is removed including the epithelium, the basement membrane, and the anterior part of the stroma. After wounding, corneas are cut from the globe, mounted on a collagen/agar base, and cultured for two weeks in supplemented-serum free medium with stabilized vitamin C to augment cell proliferation and extracellular matrix secretion by resident fibroblasts. Activation of myofibroblasts in the anterior stroma is evident in the healed cornea. This model can be used to assay wound closure, the development of myofibroblasts and fibrotic markers, and for toxicology studies. In addition, the effects of small molecule inhibitors as well as lipid-mediated siRNA transfection for gene knockdown can be tested in this system.

A protocol for an ex vivo corneal organ culture model useful for wound healing studies is described. This model system can be used to assess the effects of agents to promote regenerative healing or drug toxicity in an organized 3D multicellular environment.

The cornea has been used extensively as a model system to study wound healing. The ability to generate and utilize primary mammalian cells in two ...

Targeting Gray Rami Communicantes in Selective Chemical Lumbar Sympathectomy

Chemical lumbar sympathectomy (CLS) is a commonly used, minimally invasive procedure for the treatment of conditions including ischemic diseases of the lower extremities, hyperhidrosis, etc. It is commonly practiced to position the puncture needle tip in front of the anterior fascia of the psoas major muscle and inject the inactivating agent around the sympathetic trunk, which is defined as conventional CLS. Although relatively rare, ureteropelvic damage is the most frequently reported complication of conventional CLS and can cause serious harm to patients. We found that injecting the inactivating agent behind the anterior fascia, which only targets gray rami communicantes, helped achieve therapeutic efficacy in&#160;vasodilation, sweat reduction, and pain relief comparable to conventional CLS, and serious complications were largely reduced. We define this procedure as selective CLS. Here, we present a protocol of selective CLS. The precise needle tract and accurate evaluation of the spreading of the contrast agent are critical to ensure that the drug is injected behind the anterior fascia of the psoas major muscle. The needle tip is at approximately one-third the dividing line of the vertebral body in the lateral view of a lumbar X-ray. The contrast is mainly confined around the needle tip and spreads outward and downward along the psoas muscle fibers. In this way, the anterior fascia provides a natural barrier for the ureteropelvic area, and the psoas major muscle provides a natural barrier for the lumbar nerve root. There are several highlights of this article, including 1) a detailed description of the selective CLS procedures, 2) an explanation of the anatomical basis for the implementation of selective CLS, and 3) an explanation of the differences between selective and conventional CLS.

We present a protocol for selective chemical lumbar sympathectomy (CLS), which inactivates only gray rami communicantes and not the sympathetic trunk. Selective CLS can help achieve therapeutic efficacy in vasodilation, sweat reduction, and pain relief that are comparable to conventional CLS, and serious complications, particularly ureteropelvic damages, can be reduced.

Chemical lumbar sympathectomy (CLS) is a commonly used, minimally invasive procedure for the treatment of conditions including ischemic diseases of the ...