Effect of chronic treatment with caffeine on glycemic indices and insulin sensitivity responses in streptozotocin-induced diabetic rats

Some studies have demonstrated that acute caffeine ingestion induces reduces insulin sensitivity in healthy subjects and shift glycemic homeostasis toward hyperglycemia. So, this study aimed to investigate the caffeine treatments on some of glycemic index and insulin sensitivity responses in the serum of type 2 diabetic rats.

In experimental design, thirty male wistar rats with an age range of 3-2 months and weight range 300-250 g were randomly divided into 3 groups of homogeneous 10 rats in each group: Healthy control (C), Diabetic control (D): high-fat diet combined with a single intraperitoneal injection of streptozotocin (STZ) at a low dose 35 mg/kg-1 i.p and Diabetic with supplement (D+CA): intraperitoneal injection of pure caffeine at 70 mg/kg-1 5 days/week for 8 weeks. The 48-hours after last caffeine administration bout, fasting serum glucose and insulin levels and HOMA-IR and QUICKI were measured. Data were analyzed by one-way ANOVA for any statistical significant differences between the study groups.

The results showed that the induction of type 2 diabetes causes a significantly increase in fasting serum glucose and insulin levels (P=0.001). Whereas, caffeine administration caused exacerbated in increased serum glycemic index levels in compared to other groups (P=0.001). Also, insulin resistance and sensitivity index in diabetic groups increased and decreased, respectively (P=0.001).

Based on the results of this study, chronic caffeine treatment have deleterious  effect on glycemic homeostasis and insulin sensitivity index in type two diabetes.