Week 11 Animal grafts Flashcards
Flashcard 1: What is an animal model?
Definition:
An animal model refers to the use of animals in scientific experiments to study biological processes or test the effects of treatments that are difficult or unethical to test in humans.
Key Point:
Animal models help replicate human conditions for the development and testing of new therapies, drugs, and biomaterials.
Flashcard 2: Why are animal models important in biomaterials research?
I
mportance:
They allow researchers to evaluate the biocompatibility, safety, and effectiveness of new biomaterials before human trials.
Examples:
Testing inflammatory responses, cell engraftment, or tissue regeneration when biomaterials are implanted.
Flashcard 3: What are the ethical considerations in animal models?
Ethical Guidelines:
Animal research is governed by legislation and requires approval from independent ethics committees. Researchers must ensure care, monitoring, and pain management for the animals.
Three R’s Principle:
Refinement – Improve animal welfare by minimizing suffering.
Reduction – Use fewer animals by designing efficient studies.
Replacement – Use alternatives to animals when possible.
Flashcard 4: Which species are commonly used in animal models?
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Flashcard 4: Which species are commonly used in animal models?
Small animals:
Mice and rats are commonly used due to their cost-effectiveness and availability of genetic tools.
Large animals:
Pigs, rabbits, and sheep are used for closer physiological similarity to humans, particularly for cardiovascular and large organ studies
Flashcard 5: How do species relevance and cost affect animal model selection?
Relevance:
Larger animals (e.g., pigs, rabbits) are more similar to humans in physiology but are more expensive and harder to handle.
Costs:
Mice: $2000 for 60 samples (28-day study)
Rats: $5000 for 48 samples (24-week study)
Pigs: $80,000–100,000 for 32 samples (3-month study)
Key Point:
Small animal models are cost-effective but may not always provide the best human correlates.
Flashcard 6: What are internal controls in animal experiments?
Description:
Internal controls are used in studies where multiple samples can be implanted in the same animal. This helps reduce inter-animal variability and reduces the number of animals needed.
Example:
Subcutaneous implants in mice, where multiple materials are tested in one mouse for better comparison.
Flashcard 7: How do genetically modified mice enhance biomaterials evaluation?
Benefits:
Genetically modified mice allow for specific manipulation of genes to study their effects on disease, immune response, and biomaterial interaction.
Example:
Transgenic mice expressing bioluminescent markers, such as IL-1β luciferase mice, allow real-time imaging of inflammation after biomaterial implantation.
Flashcard 8: Case Study: Firefly Luciferase in Genetically Modified Mice
Study Objective:
To measure inflammation by tracking IL-1β expression using bioluminescence in transgenic mice.
Outcome:
Materials like silk/tropoelastin showed reduced inflammation compared to silk-only implants, helping assess biomaterial performance.
Flashcard 9: Challenges of developing new animal models
Validation:
New models must be validated against established systems to ensure that they accurately mimic human diseases or biological responses.
Time-consuming:
Developing new models requires careful planning, including testing different species, validating results, and ensuring reproducibility.
Benefit:
A well-developed model can lead to better preclinical testing, improving the chances of success in human trials.
Flashcard 10: What are the limitations of larger animal models?
Pros and Cons:
Large animals, while more physiologically similar to humans, come with higher costs and complexity in handling. Additionally, bigger is not always better; for instance, rabbits’ coronary anatomy is similar to humans, making them suitable for stenting studies.
Flashcard 11: Summary of Animal Model Basics
Common Models:
Materials are often tested in small animals like mice and rats, while larger animals may be used for more complex physiological studies.
Experimental Design:
The scope, number of samples, and time points can significantly affect the cost and complexity of the study.
Post-Analysis:
Histological analysis (like serial sectioning) is often labor-intensive but critical for understanding material performance in vivo.
Flashcard 12: Future of Animal Models in Biomaterials
Trend:
With advancements in genetic tools and imaging technologies, animal models are becoming more sophisticated, allowing researchers to track real-time changes and improve the precision of biomaterial testing.
Potential Innovations:
The development of disease-specific models and gene-editing tools like CRISPR could further improve the translational potential of animal research.
Knowledge Question:
What is an animal model, and why are they used in biomaterials research?
An animal model is an organism used in research to study biological processes or test treatments that cannot be easily studied in humans. Animal models simulate human diseases or biological responses, allowing researchers to evaluate new therapies, drugs, and biomaterials.
Application Question:
If you were tasked with developing a new cardiovascular stent, why might you choose to use a pig over a mouse as your animal model?
You would choose a pig over a mouse because pigs have a cardiovascular system that closely resembles that of humans. Their larger size allows for the use of human-sized stents, making it easier to predict how the device will function in clinical settings. Additionally, pigs’ anatomy, including blood vessels, is more comparable to humans, which is crucial when testing devices like stents.
Knowledge Question:
List the main benefits of using animal models in biomaterials evaluation.
Animal models allow researchers to evaluate the biocompatibility, safety, and effectiveness of new biomaterials before human trials. They can simulate human physiological responses, such as immune reactions or tissue integration, providing critical data.
Application Question:
A new biodegradable scaffold is being developed for tissue regeneration. Which animal model would be most suitable for evaluating long-term biocompatibility, and why?
For long-term biocompatibility testing, a large animal like a sheep would be suitable due to its longer lifespan and larger tissue structures, which are more comparable to human systems. Sheep are often used in orthopedic research because their bone structure and healing process are closer to humans than smaller animals like rats.
Knowledge Question:
Describe the three Rs (Replacement, Reduction, and Refinement) in the context of animal research ethics.
The three Rs in animal research are:
Refinement: Modifying procedures to minimize pain and distress.
Reduction: Using the fewest number of animals possible without compromising results.
Replacement: Using alternative methods, such as in vitro models, when possible, to avoid using animals.
Application Question:
How could you design a study to reduce the number of animals used while still achieving reliable results when testing a new drug-eluting stent?
To reduce the number of animals, you could design a study that uses internal controls, where multiple stents are implanted in the same animal (e.g., different stents in different arteries of the same pig). This allows direct comparison between test conditions without increasing the number of animals used.
Knowledge Question:
Identify at least two commonly used small animals and two large animals in biomaterials research.
Small animals: Mice, rats.
Large animals: Pigs, rabbits, sheep.
Application Question:
You’re designing an experiment to test bone regeneration using a new biomaterial. Would you choose rats or sheep for the study, and what factors would influence your choice?
Application Answer:
If you’re testing bone regeneration, sheep may be preferred because their bone structure and healing patterns more closely resemble human bone, particularly for large orthopedic devices. However, if the study is preliminary, rats might be used for cost efficiency and ease of handling.
Knowledge Question:
Explain how species relevance impacts the decision to use small or large animals in a study.
Species relevance refers to how closely the physiology and biology of the animal resemble humans, impacting the translation of the results to human medicine. Cost is a practical consideration, with smaller animals like mice being cheaper but less predictive of human outcomes, while larger animals like pigs are more expensive but offer closer human analogs.
Application Question:
A small biotech company has a limited budget to test a new biomaterial. Should they use mice or pigs for their preliminary testing, and why? How would the scope of the experiment change with this choice?
A small biotech company should choose mice for preliminary testing due to lower costs (~$2000 for 60 samples over 28 days). Larger animals, like pigs, would require $80,000 to $100,000, which may not be feasible for early-stage testing. Mice allow quick screening of biocompatibility before moving on to larger, more expensive models for detailed testing.
Knowledge Question:
What are internal controls, and how are they used in animal models?
Internal controls involve using the same animal to test multiple conditions, reducing variability between animals and minimizing the number of animals needed. For example, in a subcutaneous implant study, one mouse may receive four different biomaterial implants, allowing direct intramouse comparison.
Application Question:
You need to test four different formulations of a biomaterial for tissue engineering. How could you use internal controls to minimize the number of animals required while ensuring robust data collection?
You could implant four different formulations in each mouse. This way, one animal can serve as its own control, reducing the total number of animals while still gathering comparative data on how each formulation performs.