Ability of high fat diet to induce liver pathology correlates with the level of linoleic acid and Vitamin E in the diet.

Increased uptake of fat, such as through the ingestion of high fat diet (HFD), can lead to fatty liver diseases and metabolic syndrome. It is not clear whether certain fatty acids may be more pathogenic than others to the liver. Linoleic acid (LA) is the most abundant polyunsaturated fatty acid in the Western diet and its excessive consumption can lead to increased lipid peroxidation. We hypothesized that a high level of LA in HFD will contribute significantly to the hepatic steatosis and injury, whereas vitamin E (VIT-E) may reverse the effects from LA by inhibiting lipid peroxidation. To test this hypothesis, we fed mice with the following diets for 20 weeks: a standard low-fat diet (CHOW), HFD with a low level of LA (LOW-LA, 1% of energy from LA), HFD with a high level of LA (HI-LA, 8% of energy from LA), or HI-LA diet with VIT-E supplement (HI-LA + VIT-E). We found that the HI-LA diet resulted in more body weight gain, larger adipocyte area, and higher serum levels of triglycerides (TG) and free fatty acids (FFA) relative to the CHOW and LOW-LA diets. In mice fed with the HI-LA diet, severer hepatic steatosis was seen with higher levels of hepatic TG and FFA. Expression of genes related to lipid metabolism was altered in the liver by HI-LA diet, including fibroblast growth factor 21 (Fgf21), cluster of differentiation 36 (Cd36), stearoyl-CoA desaturase 1 (Scd1), and acyl-CoA oxidase 1 (Acox1). Liver injury, inflammation and fibrotic response were all enhanced in mice fed with the HI-LA diet when compared with the LOW-LA diet. Notably, addition of VIT-E supplement, which restores the proper VIT-E/PUFA ratio, significantly reduced the detrimental effects of the high level of LA. Taken together, our results suggest that a high level of LA and a low ratio of VIT-E/PUFA in HFD can contribute significantly to metabolic abnormalities and hepatic injury.

Integrated proteomic and miRNA transcriptional analysis reveals the hepatotoxicity mechanism of PFNA exposure in mice.

Perfluoroalkyl chemicals (PFASs) are a class of highly stable man-made compounds, and their toxicological impacts are currently of worldwide concern. Administration of perfluorononanoic acid (PFNA), a perfluorocarboxylic acid (PFCA) with a nine carbon backbone, resulted in dose-dependent hepatomegaly in mice (0, 0.2, 1, and 5 mg/kg body weight, once a day for 14 days) and an increase in hepatic triglycerides (TG) and total cholesterol (TCHO) in the median dose group as well as serum transaminases in the high dose group. Using isobaric tags for relative and absolute quantitation (iTRAQ), we identified 108 (80 up-regulated, 28 down-regulated) and 342 hepatic proteins (179 up-regulated, 163 down-regulated) that exhibited statistically significant changes (at least a 1.2-fold alteration and P < 0.05) in the 1 and 5 mg/kg/d PFNA treatment groups, respectively. Sixty-six proteins (54 up-regulated, 12 down-regulated) significantly changed in both of the two treatment groups. Among these 54 up-regulated proteins, most were proteins related to the lipid metabolism process (31 proteins). The mRNA analysis results further suggested that PFNA exposure not only resulted in a fatty acid oxidation effect but also activated mouse liver genes involved in fatty acid and cholesterol synthesis. Additionally, three (2 down-regulated, 1 up-regulated) and 30 (14 down-regulated, 16 up-regulated) microRNAs (miRNAs) exhibited at least a 2-fold alteration (P < 0.05) in the 1 and 5 mg/kg/d PFNA treatment groups, respectively, Three miRNAs (up-regulated: miR-34a; down-regulated: miR-362-3p and miR-338-3p) significantly changed in both of the two treatment groups. The repression effect of miR-34a on fucosyltransferase 8 (Fut8) and lactate dehydrogenase (Ldha) was confirmed by luciferase activity assay and Western blot analysis. The results implied that PFNA exerted a hepatic effect, at least partially, by miRNAs mediated post-translational protein repression.

[In vivo and in vitro effect of peptide HP-6 derived from donkey serum albumin on hematopoietic system].

OBJECTIVE: By bioinformatics method, the effect in hematopoietic system of bioactive peptide HP-6, which was obtained from donkey serum albumin and is one of the major protein components from donkey-hide gelatin, was investigated. METHOD: Human bone marrow nucleated cells (hBMNCs) and murine bone marrow stromal cells (mBMSCs) were separated and cultured with different concentration of peptide HP-6 (0.000 15, 0.001 5, 0.015, 0.15, 1.5 micromol x L(-1)). The effect on promoting proliferation of cells related to hematopoiesis in bone morrow was detected and the ultrastructure of cells after treated by HP-6 was observed through transmission electron microscope. Hemorrhage anemia mouse model and anemia mouse model induced by cyclophosphamide were established, and randomly divided into peptide HP-6 groups which were administered respectively with different doses (1, 0.1, 0.01 mg x kg(-1)) by gavage, and control group which was administered with PBS by gavage. Peripheral blood components of all mice and bone morrow cells (BMC) number of mice induced by cyclophosphamide were evaluated. RESULT: Peptide HP-6 could concentration-related promote the proliferation of hBMNCs and mBMSCs, hBMNCs got the highest reproduction rate of 152.11% and mBMSCs also got 63.52% with the concentration of 0.15 micromol x L(-1), then the reproduction rate decreased while the concentration kept increasing. The transmission electron microscope showed that ultrastructure of cells was normal after treated by HP-6.1 mg x kg(-1) peptide HP-6 significantly increased peripheral platelet and protected mouse morrow injured by cyclophoshamide. 0.1 mg x kg(-1) peptide HP-6 significantly increased peripheral platelet with relative growth rate of 77.65%, increased peripheral white blood cells count and peripheral red blood cells count, also could protect mouse peripheral blood after treated by chemotherapeutics. CONCLUSION: Peptide HP-6 could promote the proliferation of cells related to hematopoietic system, enhance mouse hemopoiesis function and the resistance to chemotherapeutic injury.