Effects of medium chain triglycerides on lipid metabolism in high-fat diet induced obese rats

This study aimed to compare the effects of three different medium chain triglycerides (MCTs) on lipid metabolism in obese rats. A high fat diet was fed to Sprague-Dawley rats to induce obesity, and then caprylic triglyceride (CYT), capric triglyceride (CT) and lauric triglyceride (LT) were synthesized and used to treat the obese rats for 12 weeks. The obesity phenotype and molecular changes related to lipid metabolism were determined. The results showed that all the three MCTs reduced the body weight (BW) and fat coefficient in obese rats, and the levels of plasma and liver lipids were also improved. Among the MCT groups, the LT group showed the lowest BW with the lowest food intake. Furthermore, three MCTs had different effects on the expression levels of lipid metabolism-related proteins (PPARs and SREBPs). The LT group performed the best among the three MCT groups in the protein expression levels. Interestingly, high-dose LT decreased the expression of the low density lipoprotein receptor (LDLR) in the liver, which impaired the transport of the very low density lipoprotein (VLDL)/low density lipoprotein (LDL) to the liver, resulting in high levels of total plasma cholesterol (TC) and LDL-c in the rats. We have for the first time found that different MCTs had different effects on the expression levels of triacylglycerol and cholesterol metabolism-related proteins in obese rats. These findings would help better understand the relationship between the health benefit and the type of MCT.