Vl 1 Flashcards
What are animal models?
Kroghs principle: (Nobel prize winner 1920 ind Physiology and Medicin)
–> for duch a large number of problems there will be some animal choice, or a few such animals, on which it can be most conveniently studied?
Why animal models?
- Biological similarities: many animals share biological similarities with humans
- Genetic Manipulation: easier to genetic manipulate animals than humans, allowing researchers to create models with specific genetic traits or mutations.
- Reproducubility: animals provide a controlled and reproducible environment for experiments
- Shorter Lifespan: animals generally have a shorter lifespan compared to humans
Example (Hibernation)
Hibernation occurs in various mammalian species.
- Body temperature is downregulated close to the freezing point.
- Heartbeat and breathing almost cease.
–> relevant for patients with severe trauma, stroke and cardiac arrest
Also important for transplantation
medicine: increasing preservability of
organs
Most common model organisms and their pro and cons.
-
Sea urchins and amphibia
Pro: obtained easily, larhe embryos
Con: Xenopus is tetraploid with 2 year generation time -
Chick
Pro: Embryos can be cultured outside of the egg and sre resistant to experimenatl manipulation
Cons: developmental genetics is difficult -
Mouse
Pro: excellent genetic (Knockout+transgenesis), evolutionary close to human.
Cons: uterine mode of development has made it difficult to analyze early development
–> But now it has become possible to culture embryos for some time outside of the uterus -
Zebrafish
Pro: easy to breed, transparent and extra-uterine mode of development. Excellent genetic tools available
Cons: part of its genom has been duplicated which may hamper the analysis of some gene function
Henriette Lacks
- treated at John Hopkins Hospital against cervical cancer
- Without her permission or knowledge, cells were taken from her cervix and an immortal cell line (HeLA cell line) was produced
- Many key discoveries and biomedical research were done on heLa cells.
- 2013, genom sequence of a strain of HeLa was published
Arguments for using animals in research
- Understanding of complex physiological or disease-relevant processes requires that they are addressed in living organisms, in particular, when analyzing the function of the nervous system, cardiovascular system, immune system, or hormonal effects
- Cell culture systems are homogeneous and the crosstalk between different cell types, tissues, and organs is missing
- Cell culture systems are slightly “artificial” and allow only limited insights into diverse life processes
- Analyzing cancer for instance requires studying the interaction of
cancer cells with neighboring cells and tissues
Basic assumptions of transferability
- transfer of reaction patterns from cell structure to the total organism can bet extremly difficult (e.g Contergan)
- studies on the complete organism are needed
- Animal experiments make it possible to predict about 70% of the adverse effect on humans
36% of substances tested in animlas studies are not used in subsequent tests on humans due to undesireable side effects and saftey risks
The legal framework of animal experimentation in Germany – historic perspective, animal protection
- “patho-inclusive” : prioritizing humans interests over those of animals. Causing distress to animals may be justified for ceratin human interests, such as life, health, knowledge gain and pleasure. Killing is okay but suffering should be avoided
-
Articel 20a: (2002)
states responsibility to protect the natural foundations of life and animals through legislation and legal actions, giving ethical treatment of animals a high legal status
–> Ethical treatment of animals has thus been given an unusually high legal status. -
3rd Amendment of Animal Welfare: (2013)
aims to enhance animal protection by raising minimum standards based on the latest scientific findings and adhering to the Three Rs principle.
Three R principal in animal experimental strategies
1. Refinement
* minimize stressful experiments
* consider animals capapcity for suffering based on neuronal development and self protetction
* provide stronger protection for animal with advanced development, like primates
NOTE: Less developed animals may react more stressfully than those adapted through training
* carefully select animal models
* alleviate pain with analgesia and anesthesia
* improve measurements procedure technology (develop non-invasiv research methods)
* enrich environment for experimental animals
2. Replacement
* explore alternatives like in vitro cell culture, in silico computer models and organ-on-a-chip technology, organoids
(complete replacement not always possible)
* since 2013, EU bans the sale of cosmetic products developed through animal experiments
3. Reduction
* Implement statistical and methodological improvements
* determine the minimum number of test animals
* centrally register and record results
Basel declaration
a set of ethical guidelines established to ensure the humane treatment of animals in scientific research, emphasizing scientific validity, the Three Rs principle, transparency, and education.
- ethical treatment
- science validity
- 3 Rs principle
- transperency and communication
- education and training
Which Animal experiments are unlawfull?
unlawfull (prohibited in principle)
➡Animal experiments related to the development of tobacco
products, detergents or cosmetics (possibility of specific
exceptions).
absolutely unlawful (absolutly prohibited)
➡Animal experiments are absolutely prohibited, if they are related
to the development and testing of weapons, ammunitions, and
related equipment.
Which animal experiments are approval?
- basic research
- prevent illness in humans and animals
- recognise physiologicals conditions in humans and animals
- promote welfare and improve treatment of farm animals
- conservation purpose
- protect environment in the interest of healt or welfare of humans and animals
- quality, effectiveness and safety of drugs, foodstuff, peticides, chemical or other hazardous substances
- for forensic examinations
- education, training and professional development
