Exercise benefits cardiovascular health in hyperlipidemia rats correlating with changes of the cardiac vagus nerve

The role of exercise training on hemodynamic parameters, blood lipid profiles, inflammatory cytokines, cholinesterase-positive nerves and muscarinic cholinergic (M₂) receptors expression in the heart was investigated in Sprague-Dawley male rats with hyperlipidemia (HL). The rats were subjected to a high-fat diet and exercise training for 8 weeks, and then the hemodynamic parameters, the profiles of blood lipid and inflammatory cytokines, and the expression of cholinesterase-positive nerves and M₂ receptors were measured. HL rats displayed cardiac dysfunction, dysregulation of inflammatory cytokines, and decreased cholinesterase-positive nerves and M₂ receptors expression. The combination of hyperlipidemia with exercise training (AT) restored the profiles of blood lipids and the levels of inflammatory cytokines. In addition, AT and HL + AT improved cardiac function with increasing cholinesterase-positive nerves and M₂ receptors expression. Overall, these data show that the increased expression of cholinesterase-positive nerves and M₂ receptors in the heart is partially responsible for the benefits of exercise training on cardiac function in hyperlipidemia rats.