Effect of 8-Week Interval Training on Protein Tyrosine Phosphatase 1B Expression in Gastrocnemius Muscle and Insulin Resistance in Rats with Type 2 Diabetes

Abstract

Background: Insulin resistance induced by genetic and metabolic disorders is the main cause of the prevalence or severity of type 2 diabetes (T2D). Protein tyrosine phosphatase 1B (PTP1B) plays a key role in regulating glucose homeostasis as a negative regulator of insulin signaling pathway. Objectives: This study aimed to assess the effect of interval training on PTP1B expression in gastrocnemius muscle and insulin resistance in male rats with T2D. Methods: T2D was induced by high fat diet (HFD) and intraperitoneal injection of STZ in 14 male Wistar rats and then they were divided randomly into exercise (n=7) or control (n=7) groups. Exercise rats completed an 8 weeks interval training (5 days/week) and control rats remained without training. Fasting glucose, serum insulin, and PTP1B expression in gastrocnemius muscle were measured 48 hours after the last exercise session. Insulin resistance was assessed using homeostasis model assessment of insulin resistance (HOMA-IR) formula based on fasting insulin and glucose levels. An independent t test was used to compare each parameter between 2 groups. A P value less than 0.05 was considered statistically significant. Results: Interval training resulted in a significant decrease in fasting glucose level (P<0.0001) and insulin resistance (P=0.018) as well as an increase in serum insulin level (P<0.0001). PTP1B expression in gastrocnemius muscle decreased significantly compared with control rats (P=0.003) Conclusion: Interval training can improve insulin resistance in T2D rats. This improvement may be attributed to the decrease in PTP1B expression in gastrocnemius muscle by interval training.