The site of fat deposition plays an important role in meat quality and body health. Biologically, the perirenal visceral fat (PF) and back subcutaneous fat (BF) are distinct. Angus and Simmental cattle (Bos taurus) were used as models. HE staining, triglyceride assay kit and RNA-seq were used to analyze the differences in tissue morphology and lipid accumulation, co-genes, and differentially expressed genes (DEGs) between the two tissues. According to the findings, BF has a smaller cell area and greater lipid deposition ability than PF. RNA-seq generated approximately 10.99 Gb of data in each library, and 23,472 genes were identified. The genes FABP4, ADIRF, and SCD that are related to adipose deposition were highly expressed in four tissues. There were 1678 DEGs and 1955 DEGs between BF and PF in Angus and Simmental cattle respectively. Gene Ontology function analysis identified several DEGs involved in metabolism. KEGG pathway analysis showed that four pathways related to fat metabolism were enriched. In the BF, seven genes (COL1A1, COL1A2, COL3A1, COL2A1, RXRA, C1QTNF7, and MOGAT2) were up-regulated. Five genes (ADRB3, ABHD5, CPT1B, CD36, LPIN1) were down-regulated. This study identified candidate genes that led to differences in fat metabolism, which could be useful in cattle breeding.

Ozone pollution is a major environmental concern. According to recent epidemiological studies, ozone exposure increases the risk of metabolic liver disease. However, studies on the mechanisms underlying the effects of ozone exposure on hepatic oxidative damage, lipid synthesis, and catabolism are limited. In this study, Huh-7 human hepatocellular carcinoma cells were randomly divided into five groups and exposed to 200 ppb O₃ for 0, 1, 2, 4, and 8 h. We measured the levels of oxidative stress and analyzed the changes in molecules related to lipid metabolism. The levels of oxidative stress were found to be significantly elevated in Huh-7 hepatocellular carcinoma cells after O₃ exposure. Moreover, the expression levels of intracellular lipid synthases, including SREBP1, FASN, SCD1, and ACC1, were enhanced. Lipolytic enzymes, including ATGL and HSL, and the mitochondrial fatty acid oxidase, CPT1α, were inhibited after O₃ exposure. In addition, short O₃ exposure enhanced the expression of the intracellular peroxisomal fatty acid β-oxidase, ACOX1; however, its expression decreased adaptively with longer exposure times. Overall, O₃ exposure induces an increase in intracellular oxidative stress and disrupts the normal metabolism of lipids in hepatocytes, leading to intracellular lipid accumulation.

The aim of this experiment was to investigate the differences in metabolites in perirenal fat (PF) between Chinese Simmental cattle and Angus cattle. Six healthy 18-month-old male Angus cattle and Chinese Simmental cattle were selected, and the perirenal adipose tissue was collected after slaughtering. HE staining, a triglyceride assay kit, and liquid chromatography–tandem mass spectrometry (LC-MS/MS) technology were used to compare and analyze the differences in the cell morphology, lipid accumulation, and metabolites of the two types of PF. The results showed that the PF of Angus cattle had a larger cell area and stronger lipid deposition ability than that of Simmental cattle. A total of 567 metabolites were detected by LC-MS/MS technology, of which 119 were significantly upregulated in Angus cattle PF and 129 were significantly upregulated in Simmental cattle PF. Differential metabolites were enriched in pathways such as fatty acid biosynthesis, polyunsaturated fatty acid biosynthesis, regulation of adipocyte lipolysis, and oxidative phosphorylation. Finally, 12 metabolites that may cause phenotypic differences between the two types of perirenal adipose tissue were screened out from these pathways. This study has preliminarily screened out biomarkers that may affect lipid metabolism in PF, providing basic data for the further exploration of the metabolic characteristics of PF.