Lecture 3 (week 2) Flashcards
What are 4 experimental models for human medical and health research
-Simulations with mathematic models/computer
-In vitro and ex vivo models
-Animal models
-Human participants
What does In vitro mean?
In glass, cultured in a dish
What does ex vivo mean?
Cells, tissues, etc taken from organism
Are the following in vitro or ex vivo?
Isolating rat gastrocnemius muscle for incubation
Ex vivo
Are the following in vitro or ex vivo?
Culturing cells
In vitro
Are the following in vitro or ex vivo?
Isolated perfused and beating heart
Ex vivo
Are the following in vitro or ex vivo?
Growing skin
In vitro
Are the following in vitro or ex vivo?
Transformed cancer cells
In vitro
What are the main purposes of in vitro and ex vivo research?
-Allows for controlled experimental conditions
-Allows for understanding fundamental mechanics
What animal models are used for experimentation?
-Nematodes and fruit flies
-Rats
-Mice
-Swine
Primates (rare)
Why do we use nematodes as an animal model?
What are some examples of uses?
-40% homology to humans
-Easy and cheap to study
-Short life cycle (3 days)
-Self-fertilizing
-Can be frozen and thawed
-Transparent so can see inside
-ex. turning off genes and pathways
-ex. use a flourescent tag to follow digestion, synthesis of proteins, cholesterol, etc
Why do we use fruit flies as animal models?
-65% homology to humans
-Life cycle & development are sensitive to environmental change
-Ex. used in neuropharmacology research to study effects of drugs & alcohol
Why do we use rats as animal models?
-Very social & intelligent
-Used to study lifestyle effects on metabolism (diets, exercise, drugs)
-Takes a “more severe approach” than with humans (E.g. 50% fat diets, 10 hours/week of very intense exercise)
-Not a very good model for human infant nutrition & metabolism
-Zucker rats lack leptin receptors & are used to study obesity & diabetes
Why do we use mice as animal models?
-Popular due to ease of applying recombinant DNA technology (knockout a gene, over-express a gene, etc.)
-Can test importance of a single protein
-Ob/ob mouse fails to secrete functional leptin, so not good to study leptin in human
-Used to study lifestyle effects on metabolism; results may differ from rats (i.e. cannot assume one rodent model is equal to another)
-E.g. takes longer to make a mouse insulin resistant on a high fat diet (vs rats)
-Muscle metabolism can differ
-Less impairment of glucose uptake in mice with high fat diet (vs rats)
* Mitochondria adapt less robustly with exercise training in mice (vs rats)
Why do we use swine as animal models?
-Piglets are best non-primate model for human infant development & metabolism
-Used to study organ transplants (xenografts)
-Cloned miniature pigs can be purchased from companies so that the animals are genetically identical
