STZ does not caused diabetes in experimental animals, it only causes hyperglycaemia which is a sign of diabetes. your treatment can cause improve in hyperglycaemia caused by STZ, this mean your result is now normoglycaemia

STZ damages beta-cells. You may check either plasma C-peptide or insulin to know whether your treatment restores beta-cell function.

Hi dear Tarek Mohamed Ali,

Good question!

As you know, diabetes is a complex metabolic disorder.its involves many pathways which ultimately lead to beta cell destruction or insulin resistance to receptors. 

STZ was discovered from the Streptomyces achromogens (a kind of soil microbe), as a new antibiotic in 1956 and also developed as a therapeutic agent for the treatment of metastatic islet cell tumor (high insulin production). In body, STZ links  to C2 position of D-glucose and glucose moiety directs its selective pancreatic beta cell uptake via GLUT-2 and...

In animal studies, STZ induced diabetic rats/mice shows complication development similar to diabetic patients. I induce type 1 diabetes in rats by removing their pancreas via surgery. After 8 weeks of surgery i saw some sings such as severe hyperglycemia,hyperlipidemia, diabetic nephropathy  (biochemically and pathologically), some relative retinopathy signs, hypogonadism and...Thus diabetic complication that develops in STZ-induced diabetic animals may be more related to hyperglycemia than STZ. However,hypoglycemic activity of some agents/drugs or herbs may be related to several insulin independent/dependent mechanisms.

I hope this answer could help you,

Good luck,

I agree with Mehran's suggestion and his idea. STZ can be used to induction both T1DM and T2DM, dependent your methods.  To sperate the damages caused by hyperglycemia from STZ, one way you may can try to set another group that only cause hyperglecemia without STZ treatment. so that youe results may can distinct each other. Best wish and good luck to you. let us know you further results.