Long-term exercise at different intensities can reduce the inflammatory response in the brains of...

Methamphetamine (METH) is a highly addictive psychoactive drug that is used worldwide. Various approaches have been used to address METH dependence, but many of them have little effect. Previous studies have shown that exercise on a treadmill could reduce METH dependence in mice, but the intensity and duration of exercise that was needed to be effective was unknown. This study investigated the effects of low- and medium-intensity treadmill exercise on methamphetamine reward in male mice via conditioned place preference (CPP) training, and the levels of the inflammatory factors IL-1β, IL-6 and TNF-α in three brain regions (cerebral cortex, hippocampus and striatum) were determined. The results showed that long-term medium-intensity exercise reduced the effects of methamphetamine on inflammation markers in the brain and CPP scores. In addition, long-term medium-intensity exercise decreased IL-1β concentrations in the cerebral cortex and hippocampus, reduced IL-6 concentrations in the striatum, and reduced TNF-α concentrations in the cerebral cortex, hippocampus, and striatum in methamphetamine-treated mice; low-intensity exercise was less effective. The results indicated that long-term medium-intensity exercise could reduce concentrations of methamphetamine-induced encephalitis factors in male mice, while low-intensity exercise was less effective in alleviating dependence and inflammatory responses. It is suggested that exercise intensity is an important factor affecting the dependence level and inflammatory responses in the brain in mice administered methamphetamine.