Effect of eight weeks of interval training on insulin signaling and neurodegeneration in the hippocampus of Methamphetamine-treated rats

This study investigated the effect of eight weeks of interval training on insulin signaling and neurodegeneration in the hippocampus of methamphetamine (METH)-treated rats. Thirty-two male Wistar rats were randomly divided into four equal groups (n = 8): saline, METH-1 (21-days of injection period), METH-2 (21-day injection period, followed by 8-week withdrawal), and METH+moderate-intensity interval training (MIT). Methamphetamine was injected intraperitoneally at 5 mg/kg per day for a period of 21 consecutive days. MIT was conducted on a treadmill at 60-65% of maximum speed, 5 days weekly for 8 weeks. At the end of the injection and training period, the hippocampal tissue of rats was extracted to evaluate the pathological changes and gene expression of related indicators. METH injection caused a disturbance in the insulin signaling pathway, resulting in increased neurodegeneration, as evidenced by a decrease in the expression of IRS-1 (p < 0.001) and Akt (p < 0.001) genes as well as an increase in the expression of GSK-3 beta (p < 0.001), APP (p = 0.007), tau (p = 0.006), p-tau (p < 0.001), and Caspases-3 (p = 0.003) genes. However, MIT significantly upregulated the expression of IRS-1 (p < 0.001) and Akt (p = 0.002), while downregulating APP (p = 0.028) and p-tau (p < 0.001). These findings suggest that MIT enhances insulin signaling activity and improves anxiety-like behaviors, thereby counteracting the detrimental effects of METH. Further studies are required to expand and validate these findings.