Abstract
Empathy plays a crucial role in the maintenance of interpersonal relationships among mammals. Remarkably, engaging in light-intensity exercise has been identified as a facilitator of empathic behavior, a phenomenon associated with the upregulation of miR-486a-3p in the insular cortex. However, it remains to cover the contribution of miR-486a-3p and the mechanisms of changing levels of that in the insular cortex with light-intensity exercise. We initially assessed the impact of light-intensity exercise (7.0 m/min, 30 min/day, five days/week for four weeks) on helping behavior, mRNA in their insular cortex, and the secretion of exosomal miR-486a-3p from their gastrocnemius muscle. Subsequently, we explored the effects of a daily intraperitoneal injection of miR-486a-3p mimic over a two-week period on helping behavior. The intervention of light-intensity exercise, which enhanced helping behavior, resulted in elevated levels of miR-486a-3p in the insular cortex and exosomal miR-486a-3p in the plasma. Interestingly, there was no significant change observed in the levels of gastrocnemius muscle-derived exosomal miR-486a-3p. Moreover, the administration of mmu-miR-486a-3p mimic exhibited a similar enhancement of helping behavior in mice. Notably, both the exercise intervention and miR-486a-3p mimic treatment led to the downregulation of Pten mRNA and upregulation of Bdnf mRNA in the insular cortex. Our findings suggest that the increase in exosomal miR-486a-3p, originating from a source other than the gastrocnemius muscle, contributes to the empathy enhancement induced by light-intensity exercise. Furthermore, it is proposed that miR-486a-3p mimics the effects of light-intensity exercise, presenting a potential avenue for treating empathy-related behaviors.