Dear Mugale, you can induce and develop diabetic nephropathy in rat using STZ injection, and then, see the pathological results in kidney sections including: glomerulopathy, necrosis and degeneration in tubules, increase of renal space, arteriolar hyalinosis and so on...
It should be possible ideally. But you have to give radical treatment and time to develop all the three in the same animal. There are however, three issues.
1. You will lose many animals to develop the model as it is difficult to have all the three conditions established in same model.
2. Will your ethical committee provide approval for such an ambitious and wasteful/expensive project (unless your aim and objectives are really of applicable interest).
3. How would you standardize such a model for statistically consistent results?
Hope this is useful.
Chronic hyperglycemia should eventually lead to retinopathy and nephropathy. In that case you will have to do a few repeat doses of streptozotocin and wait a few weeks more to see the effects.
The problem is that you may evaluate retinopathy through non-invasive methods like fundoscopy, but it will be difficult to see nephropathy unless you have twin models with one to be sacrificed to check nephropathy. That way you may first standardize the STZ dose, number of doses and timeline of the onset of the complications you are looking form. Else you have to look for an expert who could take a biopsy sample from the animal kidney for evaluation. Or may be there is some reliable indirect method which to me appears a huge confounding factor to interpret the results of the experiment.
Hope this answers your question.
And yes please post your question only once, it becomes easy to follow and keeps consistency and continuity in the answer thread.