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 (121 &#176;C for 15 min) prior to the surgery. Pack instruments in a metal container and maintain them until they are used in the surgery.</li>
	<li>Surgery platform setup: Assign a bench area of at least 60 cm x 60 cm for the operation. Clean the surface of area with 75% alcohol and cover with a disposable medical towel. Place a sterile surgical instruments pack, reagents, surgical items onto a disposable medical towel within the upper 1/3 of area. Leave the remaining 2/3 of area clean for surgical operation.&#160;Add a hotpad underneath surgical pad for thermal support.</li>
	<li>Animal preparation
	<ol>
		<li>Place the animal (C57BL/6J mice, male, 8-week old) into the induction chamber. Turn on the vaporizer at an induction level of 4% for isoflurane and 4 L/min for oxygen. After the animal is fully anesthetized, maintain the anesthetic with the nose cone and the anesthetic delivery at a level of 1.5% for isoflurane and 0.4 L/min for oxygen during surgery. Monitor the animal for respiration.</li>
		<li>Apply chlortetracycline hydrochloride eye ointment to prevent corneal dryness during the surgery.</li>
		<li>Shave the surgical area on the dorsal surface from the lower thoracic region to the top of the sacral region using a small animal trimmer. Remove the shaved fur with tissue wipes.</li>
		<li>Apply depilatory cream onto the shaved area and leave it there no longer than 3 min. Remove the cream with gauze and flush with 2 mL of 0.9% sterile saline.</li>
		<li>Place a custom-made surgical cylindrical pad (Figure 2A) under the abdomen of the mouse to raise up the lumbar spine and facilitate the surgical operation.</li>
	</ol>
	</li>
</ol>
2. Exposure of the lumbar third to lumbar fifth (L3&#8211;L5) spinous processes
<ol>
	<li>Use the index finger to touch the subcutaneous spinous processes of the lumbar vertebrae, which are more outward, and compare with thoracic vertebrae and sacral vertebrae to identify the lumbar region.</li>
	<li>Rinse the skin using 75% alcohol. Perform a 3&#8211;4 cm midline skin incision over the lumber region from the mid-thoracic region to the hip using a scalpel blade to expose the fascia.</li>
	<li>Identify the lumbar spine by the morphology of the posterior fascia inserted onto the tips of the spinous processes. In detail, the third lumbar (L3) to the first sacral (S1) fasciae are distinct from other fasciae by their &#8220;V&#8221; shapes. The last &#8220;V&#8221; tip connects to the first sacral (S1) fascia and the first &#8220;V&#8221; tip corresponds to the L3 spinous process (Figure 2B).</li>
	<li>Make the posterior paraspinous muscle incisions along the spinous processes from L3 to L5 on both sides laterally with a scalpel blade (Figure 2C). Control the incision depth towards the facets to reduce hemorrhage.</li>
	<li>Separate the muscle layers using two ophthalmic forceps to expose L3 to L5 spinous processes and supraspinous ligaments.</li>
</ol>
3. Resection of L3&#8211;L5 spinous processes along with the ligaments
<ol>
	<li>Separate individual spinous processes by cutting off interspinous ligaments using Venus shears (Figure 2D).</li>
	<li>Resect the L3&#8211;L5 spinous processes along with the interspinous ligaments with Venus shears (Figure 2E).</li>
	<li>Suture the skin incision with sterile silk braided (suture size 5.0) without reattachment of the paravertebral muscles.</li>
	<li>Apply Chlortetracycline Hydrochloride Eye Ointment to the surgical site.</li>
	<li>Administer Buprenorphine-SR (25 uL per gram of mouse weight) immediately after LSI surgery for analgesia.</li>
	<li>Place the animals in a warm chamber and monitor during recovery from the anesthesia. Monitor food and water intake before returning the animals to the home cage.</li>
	<li>Monitor the animal once daily for the first 3 days after operation. The animal should be able to have a normal appetite and should heal with no sign of pus, hemorrhage, or swelling. They may have minor impairment in locomotion.</li>
	<li>Carry out sham operations only by the detachment of the posterior paravertebral muscles from the L3&#8211;L5 vertebrae.</li>
</ol>

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The authors have nothing to disclose.

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 ...

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7.4K Views.  Shanghai University of Traditional Chinese Medicine. We developed a lumbar intervertebral disc degeneration mouse model by resection of L3–L5 spinous processes along with supra- and inter-spinous ligaments and detachment of paraspinous muscles.

Video: A Mouse Model of Lumbar Spine Instability

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. ...

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 ...

Differentiated Mouse Adipocytes in Primary Culture: A Model of Insulin Resistance

Insulin resistance is a reduced effect of insulin on its target cells, usually derived from decreased insulin receptor signaling. Insulin resistance contributes to the development of type 2 diabetes (T2D) and other obesity-derived diseases of high prevalence worldwide. Therefore, understanding the mechanisms underlying insulin resistance is of great relevance. Several models have been used to study insulin resistance both in vivo and in vitro; primary adipocytes represent an attractive option to study the mechanisms of insulin resistance and identify molecules that counteract this condition and the molecular targets of insulin-sensitizing drugs. Here, we have established an insulin resistance model using primary adipocytes in culture treated with tumor necrosis factor-&#945; (TNF-&#945;).
Adipocyte precursor cells (APCs), isolated from collagenase-digested mouse subcutaneous adipose tissue by magnetic cell separation technology, are differentiated into primary adipocytes. Insulin resistance is then induced by treatment with TNF-&#945;, a proinflammatory cytokine that reduces the tyrosine phosphorylation/activation of members of the insulin signaling cascade. Decreased phosphorylation of insulin receptor (IR), insulin receptor substrate (IRS-1), and protein kinase B (AKT) are quantified by western blot. This method provides an excellent tool to study the mechanisms mediating insulin resistance in adipose tissue.

This protocol describes the isolation of mouse preadipocytes from subcutaneous fat, their differentiation into mature adipocytes, and the induction of insulin resistance. Insulin action is evaluated by the phosphorylation/activation of members of the insulin signaling pathway through western blot. This method allows direct determination of insulin resistance/sensitivity in primary adipocytes.

Insulin resistance is a reduced effect of insulin on its target cells, usually derived from decreased insulin receptor signaling. Insulin resistance ...

Alkali Burn-Induced Corneal Neovascularization in Mice

A Mouse Model for Corneal Neovascularization by Alkali Burn

Corneal neovascularization (CoNV), a pathological form of angiogenesis, involves the growth of blood and lymph vessels into the avascular cornea from the limbus&#160;and adversely&#160;affects transparency and vision. Alkali burn is one of the most common forms of ocular trauma that leads to CoNV. In this protocol, CoNV is experimentally induced using sodium hydroxide solution in a controlled manner to ensure reproducibility. The alkali burn model is useful for understanding the pathology of CoNV and can be extended to study angiogenesis in general because of the avascularity, transparency, and accessibility of the cornea. In this work, CoNV was analyzed by direct examination under a dissecting microscope and by immunostaining flat-mount corneas using anti-CD31 mAb. Lymphangiogenesis was detected on flat-mount corneas by immunostaining using anti-LYVE-1 mAb. Corneal edema was visualized and quantified using optical coherence tomography (OCT). In summary, this model will help to advance existing neovascularization assays and discover new treatment strategies for pathologic ocular and extraocular angiogenesis.

Author Spotlight: Decoding Corneal Neovascularization with Alkali Burn Model for Future Therapeutic Strategies 

This protocol focuses on alkali burn-induced corneal neovascularization in mice. The method generates a reproducible and controllable corneal disease model to study pathological angiogenesis and the associated molecular mechanisms and to test new pharmacological agents to prevent corneal neovascularization.

Corneal neovascularization (CoNV), a pathological form of angiogenesis, involves the growth of blood and lymph vessels into the avascular cornea from the ...