Effects of High-Intensity Interval Training on Transcription Factor 7-Like 2 / Glucagon-Like Peptide-1 Axis in Pancreatic Tissue of Obese Diabetic Ratsobese diabetic rats

Genetic studies have indicated the effective role of transcription factors in insulin synthesis and secretion, especially in the case of diabetes. This study aimed to assess the effects of high-intensity interval training on transcription factor 7-like 2/ glucagon-like peptide 1 (TCF7L2 / GLP-1) axis in pancreatic tissue of obese rats with type 2 diabetes mellitus (T2DM).

For this purpose, obesity was induced in 21 male Wistar rats (weighting 220±10 g) by exposure to a high-fat diet for six weeks. Then, the rats were randomly assigned to a non-diabetic, a control T2DM, and an exercise diabetic group. Next, T2DM was induced by intraperitoneal injection of streptozotocin (25 mg/kg). The rats in the exercise group participated in a HIIT program, five times a week, for six weeks. After the intervention, TCF7L2 and GLP1 expression in the pancreas tissue was determined by real-time PCR. Serum insulin, glucose, and beta cell function were compared between the study groups. Data were analyzed using one-way ANOVA and Tukey post hoc test at a significance level of 0.05.

Induction of T2DM increased glucose level and TCF7L2 expression but decreased insulin, beta cell function, and GLP-1R expression. In addition, HIIT significantly decreased TCF7L2 expression as well as glucose level, serum insulin, and beta cell function; however, it did not significantly change GLP-1R expression compared with the control diabetes rats.

Based on the findings, the improvement of serum insulin and glucose level following HIIT may be attributed to the decrease in TCF7L2 gene expression in the pancreatic tissue of diabetic rats.