1. Wistar, Sprague Dawley, Drowsery etc. and others are available for this purpose. How can we differentiate between them?
2. Is their any specific strain requirement for a particular pharmacological activity?
3. What is the basis to decide whether a particular drug will give a good response in a rat model or a mouse model?
4. Is mice preferable over rats for anticancer studies and why?
Yes certainly there are differences between strains of rodents. You have to chose the particular strain according to the type of experiment. I am mainly concerned with the animal stroke model here. For the focal cerebral ischemia induced by MCAo, SD rat strain rat gives the more consistency in the infarct volume than that of other strains. While in global ischemia/stroke, the Wistar strain produces less variability than that of other strains. In the case of photothrombosis, mouse, especially the c57/bl6 strain, produces consistent results. So there might be variation in the results that might lead to misinterpretation of the experimental findings if we chose the wrong strain before doing the experiment. So the animal strain, their age, sex, body weight plays a vital role in the in vivo experimental success. Before preparing the final protocol for the in vivo animal studies, proper and comparative study of rodent models provides you with major benefits. Many people think this is a very simple issue but you have raised the most imp issues in animal studies.
By looking at a particular rat or mice, how can we determine its strain? what are the identifying features for each strain?
You can divide rat and mouse strains in to two basic categories: inbred and outbred. From what I have studied, if you are doing primary pharmacological testing, it is usually recommended to use inbred mouse strains (like the C57BL/6), since it can drastically reduce the variance of your results. Outbred strains (like the Swiss mouse or Sprague-Dawley rat) are usually recommended when you want to test some hypothesis that depends on genetic variability.
You should be careful with the characteristics of your strain. For example, the C57BL/Ks strain has progressive hearing loss with onset prior to three months of age, while the C57BL/6 has progressive hearing loss with onset only after 10 months of age. This could severely affect your results if, for example, you are testing a model of tinnitus or training the animals based on an auditory cue.
You also need to be very careful with the origin and genetic monitoring of rat and mouse strains. Depending on the strain, especially with closely related inbred mouse strains (e.g.: C57BL/Ks vs C57BL/6 ), it can be quite hard to differentiate them. This information should be provided by the company or breeding facility that provides you with the animals.
- Badges
- Science topic
- Similar topics
- Chemistry
- Pharmacology