I want to evaluate the therapeutic and prophylactic of a drug on RA model in rat. when i should started to administration of drug in therapeutic and prophylactic group? in some studies they started administration few days before RA onset and others initiated at the time the RA onset for therapeutic group
Dear Hamidreza
Assuming that you are going to create disease in your murine model which mimics human rheumatoid disease, your question can be simplified.
If you are going to study the therapeutic value of drug x in RA, your animal model needs to have RA. So you will have to create disease first.
When you want to study the prophylactic value of the same drug, you will have to give the drug prior to the creation of the disease.
If you are going to do both arms - do the therapeutic arm first. That way you have proof that your model can definitely cause disease. Otherwise the prophylactic arm is not going to make sense.
Incidentally, which drug are you thinking of and what is your murine disease model?
Chetan
I suggest you to go for prophylactic activity first. First of all you should take one normal control group rats and an arthritic control group. Compare them and find the time of of induction or the time of maximum arthritic index. Then you start prophylactic effect of test drug by administering it before or from the day onwards of administration of inducing agent. If you find any significant difference then you can plan for the curative or therapeutic effect of the test substance whose start of administration should be the time at which you got the peak arthritis index.
If the drug is administered before disease onset, it is considered prophylactic and if is is administered after disease onset, it is considered therapeutic. How long before or after disease onset (the drug is administered) would depend on what you want to see and would also depend on the disease and the drug.
Sometimes, you need to administer the prophylactic drug a long time before onset (not a few days) to see protection. Also if you start a therapeutic drug once the disease is well established (a long time after onset), it might not have any impact. So ultimately, when you should start administering would depend on what you want to see. A good starting point would be other papers where people have used your drug in the same disease context (RA). If there is no clear consensus, you might have to test multiple schedules to see which one gives you the best protection/cure.
hallo i already worked on collagen induced arthritis in rat, if this model is what you want to use i can help you.
arthritis onset is around 14 days after the first immunisation (there is a second immunisation on day 7) bay day 20 all the animals should develop arthritis (any animal not yet arthritic after 20 days will remain non arthritic).
if you want the prophylactic effect you should start drug administration from day 0 (a day before the immunisation). for the therapeutic effect you can start from day 14 or wait until all animals develop arthritis around day 20.
i personally recommand to start with the prophylactic effect especially if you are working with new drug, this model is a sever arthritis and if the drug have a mild effect it will not be seen in therapeutic treatment
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