Dose injected - STZ 60mg/kg I.P
Strain: wistar albino female rats
Bwt-120 to 150g
have given 5%glucose 2hr after STZ induction for 24hours
observations
after 3 days- diabetic rats - 19 out of 30
after 7 days-
mortality observed -12 out of 19 ie. 7 rats alive
As is pointed out your dose of STZ is high although the number of deaths is still very high for the dose. You really cannot produce Type 2 DM with STZ. The animals are not obese, insulin resistant etc. The low dose ( 45 mg/kg STZ) model is really a Type 1 model but less diabetic than animals given a higher dose.
Dear Alex,
I have never worked with female rats, but we have maintained male wistar rats after diabetes for a good period of time.
You can reduce the stz dose, or try male rats weighing 220 plus or minus 15g. That could be the first step. I recommend a small pilot experiment to standardize the dose. ALso try over night glucose water instead of 24h. You can administer the dose in the evening, put rats on glucose water and then in the morning rats can be placed back on normal water. I never fasted my rats prior to stz. Fasting increases responsiveness to STZ, so 60mg/kg in your case was probably a bit high.
If nothing helps, you can administer nicotinamide along with stz. I will try to get you the reference for this method. If stz dose turns out to be too high, nicotinamide prevents overt loss on NAD+, and hence may result in milder diabetes.
Dear Kumar sir,
it will be a great support if you can help me out from this situation
l
The optimum dosage we have fixed for STZ in our laboratory is 45 mg/kg. hence you can use this dose to make the rats diabetic. Also care should be taken to avoid hypoglycemia by feeding glucose. the mortality rate will be reduced by this dose and giving glucose.
hello alex
you can give 15% glucose after 2 hours and maintain body weighs between 200 to 250 g...IN our lab we are giving STZ 50mg /kg/bw
Dear Alex
You write
after 3 days- diabetic rats - 19 out of 30
after 7 days-
mortality observed -12 out of 19 ie. 7 rats alive
Obviously these 19 rats have survived the period of hypoglycemia due to beta cell lysis and insulin release...so I don't think that glucose water will solve your problem ( cant hurt either!). What is their blood sugar? if it is above 400 mg/dL, the rats may be dying of diabetes. Are the rats losing weight and becoming dehydrated after day 3 through day 7. You have created a type 1 model.
What about the 11 other rats, what is their blood sugar?. Rat notoriously recover from high doses of STZ, yet given a second injection, you may find that you can induce some form of mild diabetes or if you can phenotype by IPGTT , find that they have IGT, all of which is more consistent with a lean type 2 diabetes.
As it has been previously pointed out, reducing the STZ dose might help to decrease mortality this early mortality. In our experience, we have found that STZ sensitivity can slightly vary between different genetic strains (particularly in mice). Since you want to use a type II diabetes model you can significantly reduce the STZ dose, a pilot study will help you to define the appropriate (hyperglycemia/mortality) dose. We use up to 45 mg/kg BW with reasonable results. More improtantly fasting increases STZ sentitivity. You might want to try the STZ injections under fed conditions
As is pointed out your dose of STZ is high although the number of deaths is still very high for the dose. You really cannot produce Type 2 DM with STZ. The animals are not obese, insulin resistant etc. The low dose ( 45 mg/kg STZ) model is really a Type 1 model but less diabetic than animals given a higher dose.
How about accuracy of injection? It is very critical not to damage bladder during procedure. Did you had seen blood in the rat's urine after injection?
A mishap like that wud have surely caused quick death of experimental animals
You can go with little lesser dose and also the experiments shall be done initially with limited animals to check the suitability of induction of any disease.
Try to use 35mg/kg b.wt. for wistar/ SD rat with high fat diet.
Try to use 35mg/kg/day b.wt. for wistar/ SD rat with high fat diet (that given 4week).
- Badges
- Science topic
- Similar topics
- Medicine
- Disease
- Metabolic Diseases
- Glucose Metabolism Disorders
- Diabetes