Regulatory Effects of Yak Ghee Sphingomyelin on Lipid Metabolism Disorder and Liver Inflammation in Mice

The regulatory effect of yak ghee sphingomyelin on lipid metabolism disorder and liver inflammation in high-fatdiet (HFD)-fed mice was investigated. Thirty C57 BL/6J male mice were randomly divided into five groups: low-fat control, high-fat, high-dose sphingomyelin (1.20 g/100 g ), medium-dose sphingomyelin (0.60 g/100 g) and low-dose sphingomyelin (0.30 g/100 g). Serum lipid levels were measured using commercially available kits, and the expression levels of lipid metabolism factors such as 3-hydroxy-3-methylglutarate coenzyme A reductase (HMGCR) and stearoyl-coenzyme A desaturase 1 (SCD1), and inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in liver tissues of each group were determined by enzyme-linked immunoassay (ELISA) and fluorescence quantitative polymerase chain reaction (PCR). The results showed that yak ghee sphingomyelin reduced serum total cholesterol, triglycerides and low-density lipoprotein cholesterol levels in HFD-fed mice (P < 0.05). The greatest decrease in the total cholesterol, triglycerides, low-density lipoprotein cholesterol and blood sugar levels was observed in the high-dose sphingomyelin group, by 26.26%, 24.70%, 38.96% and 42.16%, respectively. In addition, the expression levels of the HMGCR and SCD1 genes (P < 0.05) were significantly up-regulated and the pro-inflammatory cytokines TNF-α and IL-6 (P < 0.05) in liver tissue were down-regulated by sphingomyelin compared to the high-fat group. Consequently, yak ghee sphingomyelin can improve lipid metabolism disorders caused by HFD and prevent the occurrence of liver inflammation.