MicroRNA expression profile and lipid metabolism characteristics in liver of rat undergoing high-fat diet

This study aimed to investigate the microRNA expression profile and the characteristics of lipid metabolismin the livers of rats undergoing a high-fat diet. Fifty male Sprague-Dawley (SD) rats were divided into a standard chowgroup (C group, N = 10) and a high-fat diet group (H group, N = 40). After 12 weeks, the rat body weight, body length,fat mass, and serum lipid concentration were measured. The expression profile of microRNAs and the gene and proteinexpression levels involved in lipid metabolism in rat liver were detected. Body fat and serum lipid concentrationswere all significantly higher in the H group than those in the C group (p < 0.05 or p < 0.01). The expression of 10microRNAs showed significant differences in the liver (p < 0.05). In particular, the let-7 family expression levelssignificantly increased (p < 0.05) in the H group compared with those in the C group. Compared with the C group, thehigh-fat diet resulted in low FAS, CPT1A, and ApoAI mRNA expression levels (p < 0.05 or p < 0.01) and high PPARαand FAT/CD36 mRNA expression levels in the H group rat liver (p < 0.01). Meanwhile, the protein PPARα, FAS,CPT1A, FAT/CD36, and ApoAI expression levels were all significantly lower in the H group than those in the C group(p < 0.05 or p < 0.01). In conclusion, the high-fat diet increased the body fat and serum lipid levels and altered the 10microRNA expression levels in the liver. The high-fat diet may affect hepatic carbohydrate metabolism and increaseectopic fat accumulation through let-7 family overexpression. The high-fat diet for 12 weeks decreased lipid metabolismlevel in the liver, thereby decreasing fatty acid synthesis, oxidation, and transport by down-regulating the PPARα, FAS,CPT1A, FAT/CD36, and ApoAI protein levels.