Synergistic Effects of Ad-Libitum Low-Dose Fructose Drinking and Low-Dose Streptozotocin Treatment in Wistar Rats: A Mild Model of Type 2 Diabetes

To develop a convenient animal model of T2D by pretreatment with low-dose 10% w/v fructose (FRC) solution followed by the injection of low doses of streptozotocin (STZ) in Wistar rats. For this 8-week experimental study; rats were first fed a standard chow ad-libitum diet and either tap water (n=40) or 10% w/v FRC solution (n=40) for 4 weeks. Next, rats in each category were randomly allocated to 4 subgroups (n=10 each) of low-dose STZ (25,35, and 45 mg/kg). The final mean fasting blood sugar (FBG) of FRC+STZ45 (197±55.87 mg/dl) were significantly higher than that of the STZ45 (P=0.015) and FRC (P=0.019) groups. FRC+STZ45 showed the highest insulin resistance demonstrated by insulin tolerance test [area under the curve (AUC) of insulin tolerance test; P<0.05]. AUC was not significantly different between the STZ45 and non-STZ groups and between FRC and non-FRC fed groups. Furthermore, FBG levels did not differ between FRC and non-FRC groups. Body weight measurement showed that the FRC+STZ45 group had the lowest body weight compared to all other groups. Our data provide the evidence that FRC and STZ45 synergistically could induce hyperglycemia and insulin resistance in Wistar rats. Here we presented a feasible model for initial forms of T2D by employing pretreatment with low-dose FRC solution and treatment with low-dose STZ.