Name: a mouse model of lumbar spine instability
Uploaded: 2021-04-23T13:30:00
Description: Watch this Scientific Journal Video about A Mouse Model of Lumbar Spine Instability at JoVE.com

This work was supported by the National Natural Science Foundation of China (81973607) and Essential Drug Research and Development (2019ZX09201004-003-032) from Ministry of Science and Technology of China.

The investigations described conform to the Guidelines for the Care and Use of Laboratory Animals of the National Institutes of Health and were approved by Shanghai University of Traditional Chinese Medicine Animal Care and Use Committee. All surgical manipulations were performed under deep anesthesia and the animals did not experience pain at any stage during the procedure.
1. Pre-operation preparation
<ol>
	<li>Instrument sterilization: Steam-sterilize surgical instruments in an autoclave ...

<ol>
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H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rabbit+Model+for+in+vivo+Study+of+Intervertebral+Disc+Degeneration+and+Regeneration.">Rabbit Model for in vivo Study of Intervertebral Disc Degeneration and Regeneration.</a> Journal of Korean Neurosurgical Society. 44 (5), 327-333 (2008).</li><li>Gullbrand, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+large+animal+model+that+recapitulates+the+spectrum+of+human+intervertebral+disc+degeneration.">A large animal model that recapitulates the spectrum of human intervertebral disc degeneration.</a> Osteoarthritis and Cartilage. 25 (1), 146-156 (2017).</li><li>Jin, L., Balian, G., Li, X. 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E., Coulson, W. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+collagenase+upon+the+intervertebral+disc+in+monkeys.">Effects of collagenase upon the intervertebral disc in monkeys.</a> Journal of Neurosurgery. 44 (1), 32-44 (1976).</li><li>Silva, M. J., Holguin, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LRP5-deficiency+in+OsxCreERT2+mice+models+intervertebral+disc+degeneration+by+aging+and+compression.">LRP5-deficiency in OsxCreERT2 mice models intervertebral disc degeneration by aging and compression.</a> bioRxiv. , (2019).</li><li>Nemoto, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histological+changes+in+intervertebral+discs+after+smoking+and+cessation:+experimental+study+using+a+rat+passive+smoking+model.">Histological changes in intervertebral discs after smoking and cessation: experimental study using a rat passive smoking model.</a> Journal of Orthopaedic Science: Official Journal of the Japanese Orthopaedic Association. 11 (2), 191-197 (2006).</li><li>Mulholland, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+myth+of+lumbar+instability:+the+importance+of+abnormal+loading+as+a+cause+of+low+back+pain.">The myth of lumbar instability: the importance of abnormal loading as a cause of low back pain.</a> European Spine Journal. 17 (5), 619-625 (2008).</li><li>Bian, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanosignaling+activation+of+TGF&#946;+maintains+intervertebral+disc+homeostasis.">Mechanosignaling activation of TGF&#946; maintains intervertebral disc homeostasis.</a> Bone Research. 5, 17008 (2017).</li><li>Bian, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excessive+activation+of+tgf&#946;+by+spinal+instability+causes+vertebral+endplate+sclerosis.">Excessive activation of tgf&#946; by spinal instability causes vertebral endplate sclerosis.</a> Scientific Reports. 6, 27093 (2016).</li><li>Ni, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensory+innervation+in+porous+endplates+by+Netrin-1+from+osteoclasts+mediates+PGE2-induced+spinal+hypersensitivity+in+mice.">Sensory innervation in porous endplates by Netrin-1 from osteoclasts mediates PGE2-induced spinal hypersensitivity in mice.</a> Nature Communications. 10 (1), 5643 (2019).</li><li>Liu, S., Cheng, Y., Tan, Y., Dong, J., Bian, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ligustrazine+prevents+intervertebral+disc+degeneration+via+suppression+of+aberrant+tgf&#946;+activation+in+nucleus+pulposus+cells.">Ligustrazine prevents intervertebral disc degeneration via suppression of aberrant tgf&#946; activation in nucleus pulposus cells.</a> BioMed Research International. 2019, 5601734 (2019).</li><li>Boos, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Classification+of+age-related+changes+in+lumbar+intervertebral+discs:+2002+Volvo+Award+in+basic+science.">Classification of age-related changes in lumbar intervertebral discs: 2002 Volvo Award in basic science.</a> Spine. 27 (23), 2631-2644 (2002).</li><li>Miyamoto, S., Yonenobu, K., Ono, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+cervical+spondylosis+in+the+mouse.">Experimental cervical spondylosis in the mouse.</a> Spine. 16, 495-500 (1991).</li></ol>

We developed the lumbar spine instability mouse model based on the cervical spondylosis mouse model in which the posterior paravertebral muscles from the vertebrae were detached and the spinous processes along with the supraspinous and interspinous ligaments were resected25. We performed a similar operation onto the lumbar spine, which has more prominent spinous processes. The LSI mouse model developed similar IDD in the lumbar spine.
The advantages of the LSI model inc...

Intervertebral disc degeneration (IDD) is commonly seen in aging and even young people caused by many factors1. Surgery for patients who suffer from IDD, causing low back pain and impaired movement, is usually performed at a later stage or in severe cases and has potential risks such as nonunion or infection2. Ideal non-operative treatment requires comprehensive understanding of the IDD mechanism. The IDD animal model serves as a crucial tool for studies of IDD mechanism and evaluation of IDD treatment.
Larger animals have been chosen for IDD models such as primates, sheep, goats, dogs, and rabbits due to their similarity with human anatomical structure to a great extent and the strong operability in terms of size of intervertebral discs (IVDs)3,4,5,6,7,8. However, these animal models are time-consuming and cost-intensive9. Mouse IVD is a poor representation of the human IVD based on geometrical measurements of the aspect ratio, nucleus pulposus to disc area ratio, and normalized height10. Despite the difference in size, mouse lumbar IVD segment exhibits mechanical properties similar to human IVD such as compression and torsion stiffness11. In addition, mouse IDD model has the advantage of low cost, relatively short IDD development, and more options for genetically modified animals and antibodies utilized in further mechanistic studies12,13,14,15.
Experimental-induced IDD models vary from the inducers and applications. For example, collagenase-induced extracellular matrix (ECM) degeneration is appropriate for ECM regeneration research16. Genetically modified phenotype are suitable for studying the gene function in the IDD process and in genetic therapies17. Annulus fibrosus incision and smoke models mimic trauma and non-inflammation induced IDD12,18.
Spinal instability (SI) leads to an unstable spine that is not in an optimal state of equilibrium. It can be caused by abnormal movement of a lumbar motion segment due to the weakness of the surrounding supportive tissue such as ligaments and muscles. It is also commonly seen post spinal fusion operation19. SI is considered as the main cause of IDD. Therefore, we aim to develop a SI mice model (focused on lumbar spine) that mimics the human IDD process20,21.
In the protocol, we introduced the procedure of establishing lumbar spinal instability (LSI) mouse model by the resection of lumbar third (L3) to lumbar fifth (L5) spinous processes along with the supraspinous and interspinous ligaments (Figure 1A,B). The animal model develops IDD as early as 1-week post-surgery as shown by hypertrophy and porosity in endplates (EPs). IVD volume starts to decrease 2 weeks post-surgery through 16 weeks along with increased IVD score, which indicates the degree of IDD. We believe the detailed and visualized procedure is useful for researchers to establish the LSI mouse model in their laboratory and apply to IDD research as needed.

<table>
	<tbody>
		<tr>
			<td>Chlortetracycline Hydrochloride Eye Ointment</td>
			<td>Shanghai General Pharmaceutical Co., Ltd.</td>
			<td>H31021931</td>
			<td>Prevent eye dry, Prevent wound infection</td>
		</tr>
		<tr>
			<td>C57BL/6J male mice</td>
			<td>Tian-jiang Pharmaceuticals Company (Jiangsu, CN)</td>
			<td>SCXK2018-0004</td>
			<td>Animal model</td>
		</tr>
		<tr>
			<td>Disposable medical towel</td>
			<td>Henan Huayu Medical Devices Co., Ltd.</td>
			<td>20160090</td>
			<td>Platform for surgical operation</td>
		</tr>
		<tr>
			<td>Inhalant anesthesia equipment</td>
			<td>MIDMARK</td>
			<td>Matrx 3000</td>
			<td>Anesthesia</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Shenzhen RWD Life Technology Co., Ltd.</td>
			<td>1903715</td>
			<td>Anesthesia</td>
		</tr>
		<tr>
			<td>Lidocaine hydrochloride</td>
			<td>Shandong Hualu Pharmaceutical Co., Ltd.</td>
			<td>H37022839</td>
			<td>Pain relief</td>
		</tr>
		<tr>
			<td>Medical suture needle</td>
			<td>Shanghai Pudong Jinhuan Medical Products Co., Ltd.</td>
			<td>20S0401J</td>
			<td>Suture skin</td>
		</tr>
		<tr>
			<td>Ophthalmic forceps</td>
			<td>Shanghai Medical Devices (Group) Co., Ltd. Surgical Instruments Factory</td>
			<td>JD1050</td>
			<td>Clip the skin</td>
		</tr>
		<tr>
			<td>Ophthalmic scissors(10cm)</td>
			<td>Shanghai Medical Devices (Group) Co., Ltd. Surgical Instruments Factory</td>
			<td>Y00030</td>
			<td>Skin incision</td>
		</tr>
		<tr>
			<td>silk braided</td>
			<td>Shanghai Pudong Jinhuan Medical Products Co., Ltd.</td>
			<td>11V0820</td>
			<td>Suture skin</td>
		</tr>
		<tr>
			<td>Small animal trimmer</td>
			<td>Shanghai Feike Electric Co., Ltd.</td>
			<td>FC5910</td>
			<td>Hair removal</td>
		</tr>
		<tr>
			<td>Sterile surgical blades(12#)</td>
			<td>Shanghai Pudong Jinhuan Medical Products Co., Ltd.</td>
			<td>35T0707</td>
			<td>Muscle incision</td>
		</tr>
		<tr>
			<td>Veet hair removal cream</td>
			<td>RECKITT BENCKISER (India) Ltd</td>
			<td>NA</td>
			<td>Hair removal</td>
		</tr>
		<tr>
			<td>Venus shears</td>
			<td>Mingren medical equipment</td>
			<td>Length:12.5cm</td>
			<td>Clip the muscle and spinous process</td>
		</tr>
	</tbody>
</table>

a mouse model of lumbar spine instability

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding the pathological processes and evaluating new drugs. Here, we introduced a surgically induced lumbar spine instability (LSI) mouse model that develops IDD starting from 1 week post operation. In detail, the mouse under anesthesia was operated by low back skin incision, L3&#8211;L5 spinous processes exposure, detachment of paraspinous muscles, resection of processes and ligaments, and skin closure. L4&#8211;L5 IVDs were chosen for the observation. The LSI model develops lumbar IDD by porosity and hypertrophy in endplates at an early stage, decrease in intervertebral disc volume, shrinkage in nucleus pulposus at an intermediate stage, and bone loss in lumbar vertebrae (L5) at a later stage. The LSI mouse model has the advantages of strong operability, no requirement of special equipment, reproducibility, inexpensive, and relatively short period of IDD development. However, LSI operation is still a trauma that causes inflammation within the first week post operation. Thus, this animal model is suitable for study of lumbar IDD.

The LSI mouse model is applied in the studies of IDD mechanism, IDD treatment, endplate (EP) degeneration such as sclerosis, and sensory innervation in EP20,21,22,23. The LSI mouse develops IDD and EP degenerative changes, as identified, by decreased IVD volume and height, increased EP volume, and increased IVD and EP scores.
The dissected and fixed lower thoracic an...

Watch this Scientific Journal Video about A Mouse Model of Lumbar Spine Instability at JoVE.com

A Mouse Model of Lumbar Spine Instability

We developed a lumbar intervertebral disc degeneration mouse model by resection of L3&#8211;L5 spinous processes along with supra- and inter-spinous ligaments and detachment of paraspinous muscles.

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding ...

This is a surgery to induce the mouse model offers an alternative for lumbar intervertebral disc degeneration related studies. This robust LSI mode requires no special equipment. It's reproducible and it can be used to induce the intervertebral disc degeneration in a relatively short period of time.Controlling the incision depths and the hemorrhage and perform for resection of each interspinous process are two key expense for implantation of our success for experiment. After confirming a lack of response to pedal reflex, place an anesthetized eight week old, male, C57 black six mouse onto a surgical pad in the supine position and apply ointment to the animal's eyes. Use a small animal trimmer to shave the surgical area from the lower thoracic region to the top of the sacral region and remove the shaved fur with tissue wipes.Apply depilatory cream to the shaved area using gauze to remove the cream after no more than three minutes and flush the exposed skin with two milliliters of 0.9 sterile saline. Then place a custom-made surgical cylindrical pad under the abdomen to raise the lumbar spine. To expose the L3 and L5 vertebrae use the index finger to touch the subcutaneous spinous processes of the lumbar vertebrae and palpate to compare the processes with those of the thoracic vertebrae and sacral vertebrae to identify the lumbar region.Rinse the skin with 75%alcohol, and using a dissecting microscope use a scalpel to make a three to four centimeter midline skin incision over the lumbar region from the mid thoracic region to the hip. Identify the lumbar spine by the V-shape of the posterior fascia inserted, into the tip so the spinous processes and use the scalpel to make shallow posterior paraspinous muscle incisions along the spinous processes from L3 to L5 laterally on both sides of the spine. Then use two pairs of ophthalmic forceps to separate the muscle layers to expose the L3 to L5 spinous processes and supraspinous ligaments.To separate individual spinous processes use venous sheers to cut off interspinous ligaments and to resect the L3 to L5 spinous processes and interspinous ligaments. Then use sterile number five silk braided sutures to close the skin incision without reattaching the paravertebral muscles and apply chlortetracycline hydrochloride ointment to the surgical site. 3D histomorphometric analysis allows intervertebral disc measurement, while 3D structural analysis allows quantification of the total tissue volume.The intervertebral disc volume significantly increases one week after surgery before decreasing two to 16 weeks after the procedure consistent with a decrease in the intervertebral disc height measured over the same time period. Increased cavities within the cranial endplates are also observed in LSI mice as quantified by an increased percentage of trabecular separation values greater or equal to 0.089 and a significant increase in the endplate volumes post-surgery. Model endplates exhibit a similar phenotype, indicating that LSI leads to endplate hypertrophy and an increase in cavity number.L5 vertebra volumes slightly increase post-surgery with statistical differences observed at 16 weeks. A significant decrease in the bone to total tissue volume ratio is also present 16 weeks after surgery, indicating that LSI causes vertebral bone loss at a later stage. A reduction in intracellular vacuoles of nucleus pulposus cells is also accelerated in LSI animals with increased numbers of osteoclasts observed in LSI endplates.This model can be modified by attaching different number of vertebrae, such as the fifth lumbar only, or from first lumbar to fifth lumbar.

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Research

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Biology

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Studying Age-dependent Genomic Instability using the S. cerevisiae Chronological Lifespan Model

Studies using the Saccharomyces cerevisiae aging model have uncovered life span regulatory pathways that are partially conserved in higher eukaryotes1-2. The simplicity and power of the yeast aging model can also be explored to study DNA damage and genome maintenance as well as their contributions to diseases during aging. Here, we describe a system to study age-dependent DNA mutations, including base substitutions, frame-shift mutations, gross chromosomal rearrangements, and homologous/homeologous recombination, as well as nuclear DNA repair activity by combining the yeast chronological life span with simple DNA damage and mutation assays. The methods described here should facilitate the identification of genes/pathways that regulate genomic instability and the mechanisms that underlie age-dependent DNA mutations and cancer in mammals.

Studying Age-dependent Genomic Instability using the S. cerevisiae Chronological Lifespan Model

Here we describe a set of DNA mutation assays that can be combined with the yeast chronological life span model to study the genes/pathways that regulate or contribute to genomic DNA instability during aging.

Studies using the Saccharomyces cerevisiae aging model have uncovered life span regulatory pathways that are partially conserved in higher eukaryotes1-2. ...

Generation of Mice Derived from Induced Pluripotent Stem Cells

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also produce a source of patient-matched cells for regenerative therapies. iPSCs may be generated using multiple protocols and derived from multiple cell sources. Once generated, iPSCs are tested using a variety of assays including immunostaining for pluripotency markers, generation of three germ layers in embryoid bodies and teratomas, comparisons of gene expression with embryonic stem cells (ESCs) and production of chimeric mice with or without germline contribution2. Importantly, iPSC lines that pass these tests still vary in their capacity to produce different differentiated cell types2. This has made it difficult to establish which iPSC derivation protocols, donor cell sources or selection methods are most useful for different applications.
The most stringent test of whether a stem cell line has sufficient developmental potential to generate all tissues required for survival of an organism (termed full pluripotency) is tetraploid embryo complementation (TEC)3-5. Technically, TEC involves electrofusion of two-cell embryos to generate tetraploid (4n) one-cell embryos that can be cultured in vitro to the blastocyst stage6. Diploid (2n) pluripotent stem cells (e.g. ESCs or iPSCs) are then injected into the blastocoel cavity of the tetraploid blastocyst and transferred to a recipient female for gestation (see Figure 1). The tetraploid component of the complemented embryo contributes almost exclusively to the extraembryonic tissues (placenta, yolk sac), whereas the diploid cells constitute the embryo proper, resulting in a fetus derived entirely from the injected stem cell line.
Recently, we reported the derivation of iPSC lines that reproducibly generate adult mice via TEC1. These iPSC lines give rise to viable pups with efficiencies of 5-13%, which is comparable to ESCs3,4,7 and higher than that reported for most other iPSC lines8-12. These reports show that direct reprogramming can produce fully pluripotent iPSCs that match ESCs in their developmental potential and efficiency of generating pups in TEC tests. At present, it is not clear what distinguishes between fully pluripotent iPSCs and less potent lines13-15. Nor is it clear which reprogramming methods will produce these lines with the highest efficiency. Here we describe one method that produces fully pluripotent iPSCs and "all- iPSC" mice, which may be helpful for investigators wishing to compare the pluripotency of iPSC lines or establish the equivalence of different reprogramming methods.

Generating induced pluripotent stem cell (iPSC) lines produces lines of differing developmental potential even when they pass standard tests for pluripotency. Here we describe a protocol to produce mice derived entirely from iPSCs, which defines the iPSC lines as possessing full pluripotency1.

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also ...

Validation of a Mouse Model to Disrupt LINC Complexes in a Cell-specific Manner

Nuclear migration and anchorage within developing and adult tissues relies heavily upon large macromolecular protein assemblies called LInkers of the Nucleoskeleton and Cytoskeleton (LINC complexes). These protein scaffolds span the nuclear envelope and connect the interior of the nucleus to components of the surrounding cytoplasmic cytoskeleton. LINC complexes consist of two evolutionary-conserved protein families, Sun proteins and Nesprins that harbor C-terminal molecular signature motifs called the SUN and KASH domains, respectively. Sun proteins are transmembrane proteins of the inner nuclear membrane whose N-terminal nucleoplasmic domain interacts with the nuclear lamina while their C-terminal SUN domains protrudes into the perinuclear space and interacts with the KASH domain of Nesprins. Canonical Nesprin isoforms have a variable sized N-terminus that projects into the cytoplasm and interacts with components of the cytoskeleton. This protocol describes the validation of a dominant-negative transgenic mouse strategy that disrupts endogenous SUN/KASH interactions in a cell-type specific manner. Our approach is based on the Cre/Lox system that bypasses many drawbacks such as perinatal lethality and cell nonautonomous phenotypes that are associated with germline models of LINC complex inactivation. For this reason, this model provides a useful tool to understand the role of LINC complexes during development and homeostasis in a wide array of tissues.

Nuclear envelope proteins play a central role in many basic biological processes and have been implicated in a variety of human diseases. This protocol describes a new Cre/Lox-based mouse model that allows for the spatiotemporal control of LINC complexes disruption.

Nuclear migration and anchorage within developing and adult tissues relies heavily upon large macromolecular protein assemblies called LInkers of the ...

Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current blastocyst injection protocol. Here we report that a simple rotation of the embryo, and injection through Trans-Inner cell mass (TICM) increased the percentage of chimeric mice from 31% to 50%, with no additional equipment or further specialized training. 26 different inbred clones, and 35 total clones were injected over a period of 9 months. There was no significant difference in either pregnancy rate or recovery rate of embryos between traditional injection techniques and TICM. Therefore, without any major alteration in the injection process and a simple positioning of the blastocyst and injecting through the ICM, releasing the ES cells into the blastocoel cavity can potentially improve the quantity of chimeric production and subsequent germline transmission.

Here we present a protocol to increase chimera production without the use of new equipment. A simple orientation change of the embryo for injection can increase the number of embryos produced, and potentially reduce the timeline to germline transmission.

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current ...

A Mouse Model of Intestinal Partial Obstruction

Intestinal obstructions, that impede or block peristaltic movement, can be caused by abdominal adhesions and most gastrointestinal (GI) diseases including tumorous growths. However, the cellular remodeling mechanisms involved in, and caused by, intestinal obstructions are poorly understood. Several animal models of intestinal obstructions have been developed, but the mouse model is the most cost/time effective. The mouse model uses the surgical implantation of an intestinal partial obstruction (PO) that has a high mortality rate if it is not performed correctly. In addition, mice receiving PO surgery fail to develop hypertrophy if an appropriate blockade is not used or not properly placed. Here, we describe a detailed protocol for PO surgery which produces reliable and reproducible intestinal obstructions with a very low mortality rate. This protocol utilizes a surgically placed silicone ring that surrounds the ileum which partially blocks digestive movement in the small intestine. The partial blockage makes the intestine become dilated due to the halt of digestive movement. The dilation of the intestine induces smooth muscle hypertrophy on the oral side of the ring that progressively develops over 2 weeks until it causes death. The surgical PO mouse model offers an in vivo model of hypertrophic intestinal tissue useful for studying pathological changes of intestinal cells including smooth muscle cells (SMC), interstitial cells of Cajal (ICC), PDGFR&#945;+, and neuronal cells during the development of intestinal obstruction.

Intestinal obstructions are a partial or complete blockage of the intestine that can cause severe abdominal pain, nausea, vomiting, and preventing the passage of stool. This procedure for creating intestinal partial obsructions in mice is reliable in studying the mechanisms underlying pathological cell growth and death in the intestine.

Intestinal obstructions, that impede or block peristaltic movement, can be caused by abdominal adhesions and most gastrointestinal (GI) diseases including ...

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer progression. How the chromosomal location and function of a centromere (i.e., centromere identity) are determined and participate in accurate chromosome segregation is a fundamental question. CENP-A is proposed to be the non-DNA indicator (epigenetic mark) of centromere identity, and CENP-A ubiquitylation is required for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability.
Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-CENP-A K124R mutant suggesting that ubiquitylation at a different lysine is induced because of the EYFP tagging in the CENP-A K124R mutant protein. Lysine 306 (K306) ubiquitylation in EYFP-CENP-A K124R was successfully identified, which corresponds to lysine 56 (K56) in CENP-A through mass spectrometry analysis. A caveat is discussed in the use of GFP/EYFP or the tagging of high molecular weight protein as a tool to analyze the function of a protein. Current technical limit is also discussed for the detection of ubiquitylated bands, identification of site-specific ubiquitylation(s), and visualization of ubiquitylation in living cells or a specific single cell during the whole cell cycle.
The method of mass spectrometry analysis presented here can be applied to human CENP-A protein with different tags and other centromere-kinetochore proteins. These combinatory methods consisting of several assays/analyses could be recommended for researchers who are interested in identifying functional roles of ubiquitylation.

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A EYFP-CENP-A

CENP-A ubiquitylation is an important requirement for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability. Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A) protein.

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer ...

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

Transgenic mouse models are powerful for understanding the critical genes controlling osteoclast differentiation and activity, and for studying mechanisms and pharmaceutical treatments of osteoporosis. Cathepsin K (Ctsk)-Cre mice have been widely used for functional studies of osteoclasts. The signal transducer and activator of transcription 3 (STAT3) is relevant in bone homeostasis, but its role in osteoclasts in vivo remains poorly defined. To provide the in vivo evidence that STAT3 participates in osteoclast differentiation and bone metabolism, we generated an osteoclast-specific Stat3 deletion mouse model (Stat3 fl/fl; Ctsk-Cre) and analyzed its skeletal phenotype. Micro-CT scanning and 3D reconstruction implied increased bone mass in the conditional knockout mice. H&#38;E staining, calcein and alizarin red double staining, and tartrate-resistant acid phosphatase (TRAP) staining were performed to detect bone metabolism. In short, this protocol describes some canonical methods and techniques to analyze skeletal phenotype and to study the critical genes controlling osteoclast activity in vivo.

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

This protocol describes a canonical method to understand the critical genes controlling osteoclast activity in vivo. This method uses a transgenic mouse model and some canonical techniques to analyze skeletal phenotype.

Transgenic mouse models are powerful for understanding the critical genes controlling osteoclast differentiation and activity, and for studying mechanisms ...

A Mouse Model of Ankle-Subtalar Complex Joint Instability

Ankle sprains are perhaps the most common sports injuries in daily life, often resulting in instability of the ankle-subtalar complex joint (ASCJ), and can eventually lead to post-traumatic osteoarthritis (PTOA) in the long term. However, due to the complexity of the injury mechanism and the clinical manifestations, such as ecchymosis, hematoma, or tenderness in the lateral foot, there is no clinical consensus on diagnosing and treating ASCJ instability. Since the musculoskeletal structure of the bones and ligaments of the mouse hindfoot is comparable to that of humans, an animal model of ASCJ instability in mice was established by the transection of ligaments around the ASCJ. The model was well-validated through a series of behavioral tests and histological analyses, including a balance beam test, a footprint analysis (an assessment of exercise level and balance ability in mice), a thermal nociception assessment (an assessment of foot sensory function in mice), micro-computed tomography (CT) scanning, and section staining of the articular cartilage (an assessment of articular cartilage damage and degeneration in mice). The successful establishment of a mouse model of ASCJ instability will provide a valuable reference for clinical research on the injury mechanism and result in better treatment options for ankle sprain.

The ankle-subtalar complex joint (ASCJ) is the core of the foot and plays a key role in balance control in daily activities. Sports injuries often lead to instability in this joint. Here, we describe a mouse model of ligament transection-induced instability of the ASCJ.

Ankle sprains are perhaps the most common sports injuries in daily life, often resulting in instability of the ankle-subtalar complex joint (ASCJ), and ...

A Calcium Phosphate-Induced Mouse Abdominal Aortic Aneurysm Model

An abdominal aortic aneurysm (AAA) is a life-threatening cardiovascular disease that occurs worldwide and is characterized by irreversible dilation of the abdominal aorta. Currently, several chemically induced murine AAA models are used, each simulating a different aspect of the pathogenesis of AAA. The calcium phosphate-induced AAA model is a rapid and cost-effective model compared to the angiotensin II- and elastase-induced AAA models. The application of CaPO4 crystals to the mouse aorta results in elastic fiber degradation, loss of smooth muscle cells, inflammation, and calcium deposition associated with aortic dilation. This article introduces a standard protocol for the CaPO4-induced AAA model. The protocol includes material preparation, the surgical application of the CaPO4&#160;to the adventitia of the infrarenal abdominal aorta, the harvesting of aortas to visualize aortic aneurysms, and histological analyses in mice.

This protocol describes a calcium phosphate-induced abdominal aortic aneurysm (AAA) mouse model to study the pathological features and molecular mechanisms of AAAs.

An abdominal aortic aneurysm (AAA) is a life-threatening cardiovascular disease that occurs worldwide and is characterized by irreversible dilation of the ...