Type 2 diabetes is associated with an increased risk of depression. In order to investigate the mechanisms involved, changes in leptin and BDNF in the hippocampus of diabetic rats have been investigated. For this purpose, 12 male rats, approximately 6 weeks old and weighing 180±20 g, were purchased from the Pasteur Institute and after two weeks of familiarization with the laboratory environment and treadmill training, were made diabetic by intraperitoneal injection of streptozotocin. After performing the tail-hanging depression test, they were randomly divided into two groups: control and exercise. The exercise group performed interval training for 6 weeks, and the control group continued their normal lives. Finally, 48 hours after the last training session and after performing the depression test, the rats were sacrificed and their hippocampal tissue samples were isolated and sent to the laboratory for cellular evaluation using the ELISA method. The results of the independent t-test showed that six weeks of interval training on a treadmill reduced depression in diabetic rats (p=0.21). Interval training also increased leptin and BDNF in the hippocampal tissue compared to the control group (p=0.001, p=0.000, respectively). It seems that BDNF, as an indicator of brain growth, and leptin, a hormone involved in insulin resistance and obesity, could be part of the mechanisms involved in the decreasing change in the depressive process in rats in response to interval training.