Unfortunately STZ can be very tricky to use. It's effects depend on whether the animal was starved overnight or not and the dose used is strain dependent. Different batches of STZ will also give different effects although the dose needed will be in the same ball park Finally, it's effect changes over time if stored made up so needs to be made up fresh every time to get consistent results. If overdosed it can cause extensve tissue damage the liver in particular seeming to take a hit although I have not investigated this in detail. What experience do you have of using STZ ?
I have attached a paragraph from one of my postgraduate students thesis, that may help. This is mice not rats but sets out the principles.
Sir Thank you very much for your clarification. I made to induce the diabetes in rats (40 mg/kg body weight STZ). It is the low dose, but in my experiment 50% mortality appeared and the other rats blood glucose levels reached upto 600 mg/dL. I thought that the delayed IP injection of STZ leads to this mortality rate.
As above, unfortunately published doses do not always help. Well not quite true, they do give a starting point. But only a starting point. It sounds as if you are right at the top end of the dose you need for your animals in your experimental conditions with this batch of STZ. I would encourage you to fast the animals overnight (just remove chow but NOT water last thing) and then do STZ injections first thing next morning. This removes one variable that will alter responses. I would suggest also that you do a dose finding experiment. May feel like time wasted but in the long run will save you much time. This is all about controlling the variables I outlined above. When you titrate the dose (probably only need three animals each group) work down from your current dose. Good luck!
Thank you very much for your clarification sir. I need to clarify one more thing sir. Is the STZ induced diabetes can be recover automatically in rats after induction or not (within 30 days)? And i have to isolate the compound from the Plant powder. Please tell me some of the institutes to isolate the compound from the plant powder.
Unfortunately beta cells can recover following STZ. STZ induced diabetes is a model that you really need some experience with having worked out protocols that work for you and that you know you can reproduce so that you have confidence in your results. However, it can be a very useful model if you think through very carefully what you need from the model. It is not really a model of T1DM or T2DM in my opinion, which is why I refer to STZ induced diabetes. If you simply need hyperglycaemic animals it works well. Most of my work was with transplantation so we just needed animals with high blood sugars to see if the transplants worked. We also used a single dose model as we did not want the transplants to be affected by further STZ administration. I realise this is not directly relevant to your work but I hope to illustrate that you just need to think through carefully what your experiment needs. Your control group will address the possibility of recovery if numbers are sufficient. Given the instability of STZ, if you are treating a large number of animals I would alternate treatments with one animal from experimental group then one from control group then one from experimental group and so on. If you do this you will have a good control group and be able to show that you understand the problems with use of STZ.
I am afraid I cannot recommend an institute to isolate your compound but I am sure there are other people on research gate who can.
Once more good luck!
Sir,
I really thank you for your ideas related to my questions. It was very useful for me.
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