LAD-Ligation: A Murine Model of Myocardial Infarction
October 14th, 2009
This video demonstrates how to use a fast and reliable model to study pathobiological and pathophysiological processes of myocardial ischemia.
A midline cervical incision is performed to expose the trachea and a small hole is cut into the trachea for insertion of an endotracheal tube. The mouse is turned on its right side and a left sided thoracotomy is performed between the third and fourth ribs. The heart is exposed and the LAD is ligated with a single stitch.
After placement of a chest tube and closing of the incision, the thorax is drained by aspirating the syringe carefully. Finally, the mouse is turned on. Its back.
The tracheal tube is removed and the trachea and cervical incision are closed. Hi, I am Sonya Refa. I'm professor in Immunology and cardiac surgery in the Department of Cardiovascular Surgery at the University Heart Center in Hamburg.
My laboratory is focusing on stem cell immunobiology and transplant immunology. Today we'll introduce you to the LID ligation model. We use this model in our lab to study the effect of stem cell therapy to generate the heart after myocardial infarction.
And I'm KA Wan, a student at Stanford University and a summer fellow in Drer's TSI Laboratory. And I am Mandy Cooch from the TSI Laboratory of the University Heart Center Hamburg. I will show you how to perform in a lady ligation and later we will show you how to verify the success of a myocardial infarction using different methods.
So let's get started. Shave the neck area and the left side of the rib cage of the anesthetized mouse. Place the mouse on its back and place a face mask over its nose and mouth to maintain anesthesia with 2%isof fluorine disinfect.
Using beta isod before starting the surgery, pinch the tail and hind feet of the mouse to confirm that it is sufficiently anesthetized. Under microscopic view, perform a midline cervical incision separating the skin muscle and tissue covering the trachea. Once the trachea is exposed, cut a small hole into the tissue between two cartridge rings below the glottis to insert the endotracheal tube.
Insert the endotracheal tube while holding the cranial part of the trachea. Using microsurgical forceps, check that thoracic movement to make sure that both lungs are well ventilated. The respiration rate should be approximately 110 per minute with an inspiratory pressure of 17 to 18 centimeters.H2O.
Turn the mouse carefully and lay it on its right side while you face its left side. Perform a left sided thoracotomy between the third and the fourth rib and dissect the tissue and muscle. Carefully use a coer to prevent bleeding.
Open the thorax carefully. Once the thorax is opened, find the heart without touching the lung with any sharp objects. Next, remove the part of the pericardial sac that is covering the heart.
The LAD is located between the pulmonary artery and the left Oracle ligate. The proximal LAD with one single eight oh proline suture. Place an endotracheal tube 28 gauge ven catheter between the fourth and the fifth rib.
Close the thoracic incision in layers using six oh proline running sutures to adapt the ribs and four oh proline running sutures. To close the skin, drain the thorax carefully with the help of a two milliliter syringe. After draining the thorax, place the mouse on its back.
Place the face mask on the mouse and take the endotracheal tube out. Adapt the tracheal cartridge rings with one single stitch using seven oh prolene sutures and close the skin using four oh prolene running sutures. We have shown that the LAD ligation mouse model is an elegant and reliable technique to create a myocardial infarction.
There are different ways to confirm a successful myocardial infarction. One method is the troponin test in which 150 microliters of blood from the mouse is applied to a customized troponin test kit. A positive result where two lines appear after a few minutes indicates the release of troponin T from the heart due to tissue injury.
A second approach to confirm a successful myocardial infarction is disdain cross-sections of the heart with 2 3 5 trien tetra oleum chloride or TTC to measure tissue viability and evaluate the infarct size. The heart is covered with TTC and incubated at 37 degrees Celsius for 20 minutes. The viable tissue will appear red while the infarcted area will appear white.
Finally, the heart of the mouse can be paraffin, embedded and sectioned for histology. Sections are stained with tri chrome to visualize fibrotic tissue. I have just shown you how to perform an LID ligation in mice afterwards.
We have shown you different methods how to confirm the successful myocardial infarction either hours after LID ligation or weeks later in performing in an LID ligation. It is important to stay away from the lung tissue to avoid lung injury. So that's it.
Thank you very much for watching the video and good luck with your experiments.
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Overview
This video demonstrates a reliable model for studying myocardial ischemia, focusing on the surgical techniques involved in the procedure.
Key Study Components
Area of Science
- Neuroscience
- Cardiovascular Biology
- Pathophysiology
Background
- Myocardial ischemia is a critical condition affecting heart function.
- Understanding its pathobiological processes is essential for developing treatments.
- Animal models are commonly used to study these processes.
- This video outlines the surgical approach for inducing myocardial ischemia in a mouse model.
Purpose of Study
- To demonstrate a surgical model for studying myocardial ischemia.
- To provide insights into the pathophysiological changes during ischemia.
- To facilitate research in cardiovascular diseases.
Methods Used
- Midline cervical incision to expose the trachea.
- Insertion of an endotracheal tube for ventilation.
- Left-sided thoracotomy to access the heart.
- Ligation of the left anterior descending artery (LAD) to induce ischemia.
Main Results
- Successful induction of myocardial ischemia in the mouse model.
- Demonstration of surgical techniques for future studies.
- Potential for further research into ischemic heart disease.
Conclusions
- The model provides a reliable method for studying myocardial ischemia.
- It can be used to explore therapeutic interventions.
- Understanding these processes is vital for advancing cardiovascular research.
Frequently Asked Questions
Executive Industry Relevance
The LAD ligation murine model provides a robust platform for interrogating the mechanisms of myocardial infarction and evaluating therapeutic interventions in a controlled, reproducible setting. This model enables high-fidelity simulation of infarction-related ischemia, supporting predictive confidence in early cardiovascular target validation and translational research. Its precision and correlation with histological outcomes make it a cornerstone for preclinical cardiac R&D pipelines.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables mechanistic de-risking by modeling acute and chronic myocardial injury in vivo.
- Supports functional target validation for cardiac repair and regeneration strategies.
- Facilitates hypothesis-driven evaluation of immunobiological and pathophysiological pathways post-infarction.
Screening & Assay Development
- Provides a validated system for quantitative assessment of cardiac injury biomarkers such as troponin T.
- Enables reproducible measurement of infarct size using TTC staining and histological analysis.
- Supports standardization of preclinical efficacy assays for candidate therapeutics targeting myocardial repair.
Translational & Preclinical Research
- Aligns with disease-relevant endpoints for translational biomarker development in cardiovascular research.
- Ensures continuity from mechanistic discovery to preclinical validation of regenerative and immunomodulatory therapies.
- Reduces translational risk by closely mimicking human infarction pathophysiology in a scalable model.
Pipeline & Workflow Integration
This model integrates seamlessly from early discovery through lead identification and preclinical validation in cardiovascular drug development.
- Discovery Biology: Supports rigorous hypothesis testing and pathway clarification for myocardial injury and repair.
- Screening: Delivers reproducible, quantitative outputs for biomarker and efficacy assessment.
- Analytics: Enables comparative analysis of tissue viability, infarct size, and biomarker release across experimental conditions.
- Translational Research: Provides a bridge to clinical relevance through alignment with human disease mechanisms.
- Enterprise Reuse: Serves as a standardized, reusable platform for diverse cardiac R&D initiatives.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in cardiac target validation.
- Operational Value: Enhances reproducibility and scalability of preclinical cardiovascular studies.
- Strategic Value: Informs go/no-go decisions and optimizes resource allocation in cardiac drug portfolios.
- Portfolio Impact: Supports risk-adjusted prioritization and advancement of cardiovascular therapeutic candidates.
Implementation Considerations
- Requires expertise in microsurgical techniques and murine anesthesia management.
- Demands access to specialized instrumentation for surgery, biomarker assays, and histological analysis.
- Necessitates cross-team standardization of surgical and analytical protocols for reproducibility.
- Adaptation may be needed for different rodent strains or comorbid models.
- Careful procedural execution is critical to avoid confounding variables such as lung injury.
