Effect of vildagliptin and metformin on anxiety in streptozotocin induced diabetic rats

Diabetes mellitus is caused by insulin secretion deficiency or a disorder in its action. Vildagliptin and metformin are two of the most recognized drugs that are used in the treatment of type 2 diabetes mellitus. The study aimed to compare the effects of metformin, vildagliptin, and their combined effect in altering behaviours of streptozocin-induced diabetic rats. For this purpose, after 10 of 50 male Wistar rats were separated as the control group (C), diabetes was induced in the others with streptozotocin. After separation of 10 diabetic control group (D), other diabetic animals were divided into 3 and treated with 500 mg/kg metformin (DM), 50 mg/kg vildagliptin (DV) and a combination of both (DMV) for 15 days. The animals were then subjected to open field and elevated plus maze testing. In the open field test, while the number of rearing increased in the group with diabetes (p<0.001), it was significantly decreased in the metformin, vildagliptin and combined treatment group compared to the diabetic control group (p<0.001, p<0.01, and p<0.001, respectively). While the time spent in the center decreased in the D and DM groups compared to the C group (p<0.05), the time spent in the combined treatment group in the center was longer than in all other diabetes groups (p<0.01). The time spent in the periphery was also decreased in the DMV group compared to the other groups with diabetes (p<0.05). The number of urinations increased in the D, DM and DV groups compared to the control group, and decreased in the DMV group compared to the diabetic groups. While the number of defections increased in the D group compared with the C group (p<0.01), it was decreased in the DMV group compared to the D group (p<0.05). In the elevated plus maze test, while the time spent in enclosed arms increased in the group with diabetes compared with the C group (p<0.05), there was no difference in the treatment groups compared to the D group. As a result, our study showed that the effects of vildagliptin and metformin on anxiety in diabetic animals were not evident when they were used alone; also, it showed that combined treatments can be effective in reducing anxiety caused by diabetes.