Melatonin Modulates Lipid Metabolism and Reduces Cardiovascular Risk in Apolipoprotein E-Deficient Mice Fed a Western Diet

Melatonin (MLT), a natural compound found in the animal and vegetable kingdom, participates in several physiological processes. MLT exerts antioxidant and anti-inflammatory activities, among others, but information about its action on lipid metabolism is still scarce. For this reason, mice deficient in apolipoprotein E (ApoE−/−) fed a Western diet (WD) were intragastrically treated with different concentrations of MLT (2 and 9 mg/kg) for 12 weeks. The lipid parameters were quantified, and, since links between cardiovascular risk and immune function and oxidative stress have been established, we also analyzed the population of leukocytes and the oxidative stress status. Although there was no change in the weight of the mice, a significant reduction in low-density lipoprotein cholesterol (LDL-C) was observed in mice treated with the higher concentration of MLT tested in this study. Additionally, an improvement in cardiovascular risk indexes was observed. A reduction in the hepatic total cholesterol (TC) and LDL-C levels was also observed in the treated mice. Finally, a decrease in leukocytes and lymphocytes in particular, as well as an increase in the antioxidant status, were shown in MLT-treated mice. In conclusion, MLT is a promising candidate that could be considered as a possible functional ingredient capable of preventing cardiovascular risk.