Effect of Eight Weeks of High Intensity Interval Training on Tissue Changes and Gene Expression of APP and Tau Indices in the Hippocampus of Rats Addicted to Methamphetamine

Introduction: The use of methamphetamine (METH) can cause neurotoxicity. The purpose of this research was to investigate the effect of high intensity interval training on tissue changes and gene expression of neurodegeneration indicators in the hippocampal tissue of methamphetamine-dependent rats. Methods: In this experimental research, 32 male rats were divided into four equal groups of saline, primary methamphetamine (METH-1), methamphetamine+training (METH+HIT) and secondary methamphetamine (METH-2). METH was injected at the dose of 5 mg/kg body weight for 21 days. The exercise program (5 sessions per week) included interval training (4 sets of 2 minutes with high intensity and 2 to 4 minutes of active rest between sets) on a treadmill. At the end of the injection and training period, the hippocampus tissue of the rats was extracted to evaluate the pathological changes and gene expression of related indicators. Data were analyzed using one-way ANOVA test at the significance level of (P≥0.05) by GraphPad software. Results: The results of gene expression in the hippocampal tissue showed that along with METH injection, the expression of α-syn, GSK-3β, CDK5, APP, Tau and p-Tau indicators increased significantly;  nevertheless the exercises (HIT) decreased the expression of the genes of the current research. Pathological studies showed that METH injection caused a significant increase in the destruction of neurons in the CA1 region of the hippocampus, and performing intense intermittent exercise had significantly reduced the destruction of neurons. Conclusion: Methamphetamine has caused intoxication and neurodegeneration, and HIT training has been able to improve these conditions to some extent. More research is needed in this field to reach general conclusions.