Comparative proteomic analysis of fibrotic liver of rats fed high fat diet contained lard versus corn oil.

INTRODUCTION: The influences of dietary fatty acids on the progress of chronic liver diseases have attracted lots of attentions, but the mechanisms of the effects of lipids rich in saturated fatty acids or PUFAs on hepatic fibrogenesis remain unclear. METHODS: Female Fischer 344 rats were fed normal chow or chow plus 20% (w/w) of corn oil or lard, respectively, and injected CCl4 twice a week for 4 weeks to induce liver fibrosis. Masson's staining was adopted to illustrate the fibrosis level. The mRNA expression level of α-SMA and the DNA methylation level of its promoter region were analyzed. A 2-DE gel based proteomic approach was constructed to investigate the differential expression level of hepatic proteome between three diet groups. RESULTS: Histological evaluations and α-SMA expression analysis illustrated the high corn oil intake has no effects on hepatic fibrogenesis, but lard intake aggravated liver fibrosis, partly attributed to DNA demethylation of α-SMA promoter region. 2-DE Gel based proteomic study demonstrated excessive lard consumption elevated the expression of fibrosis related alpha-1-antitrypsin precursor, and endoplasmic reticulum stress related proteins such as heat shock cognate 71 kDa, eukaryotic translation initiation factor 4A1 and protein disulfide isomerase associated 3. Moreover, unlike corn oil rich in PUFAs, lard had no effects to elevate the expression of glutathione S-transferases, but decreased the expression of iron store related proteins heme binding protein 1 and ferritin. CONCLUSIONS: Lard intake aggravates CCl4 induced liver fibrosis via enhancing the expression of fibrogenesis and ER stress related proteins, and disturbing the hepatic transmethylation reaction.

Neuroprotective mechanism of Lycium barbarum polysaccharides against hippocampal-dependent spatial memory deficits in a rat model of obstructive sleep apnea.

Chronic intermittent hypoxia (CIH) is a hallmark of obstructive sleep apnea (OSA), which induces hippocampal injuries mediated by oxidative stress. This study aims to examine the neuroprotective mechanism of Lycium barbarum polysaccharides (LBP) against CIH-induced spatial memory deficits. Adult Sprague-Dawley rats were exposed to hypoxic treatment resembling a severe OSA condition for a week. The animals were orally fed with LBP solution (1 mg/kg) daily 2 hours prior to hypoxia or in air for the control. The effect of LBP on the spatial memory and levels of oxidative stress, inflammation, endoplasmic reticulum (ER) stress, apoptosis and neurogenesis in the hippocampus was examined. There was a significant deficit in the spatial memory and an elevated level of malondialdehyde with a decreased expression of antioxidant enzymes (SOD, GPx-1) in the hypoxic group when compared with the normoxic control. In addition, redox-sensitive nuclear factor kappa B (NFКB) canonical pathway was activated with a translocation of NFКB members (p65, p50) and increased expression levels of NFКB-dependent inflammatory cytokines and mediator (TNFα, IL-1ß, COX-2); also, a significantly elevated level of ER stress (GRP78/Bip, PERK, CHOP) and autophagic flux in the hypoxic group, leading to neuronal apoptosis in hippocampal subfields (DG, CA1, CA3). Remarkably, LBP administration normalized the elevated level of oxidative stress, neuroinflammation, ER stress, autophagic flux and apoptosis induced by hypoxia. Moreover, LBP significantly mitigated both the caspase-dependent intrinsic (Bax, Bcl2, cytochrome C, cleaved caspase-3) and extrinsic (FADD, cleaved caspase-8, Bid) signaling apoptotic cascades. Furthermore, LBP administration prevented the spatial memory deficit and enhanced the hippocampal neurogenesis induced by hypoxia. Our results suggest that LBP is neuroprotective against CIH-induced hippocampal-dependent spatial memory deficits by promoting hippocampal neurogenesis and negatively modulating the apoptotic signaling cascades activated by oxidative stress and inflammation.

Differential protective effects of extra virgin olive oil and corn oil in liver injury: a proteomic study.

Extra virgin olive oil (EVOO) presents benefits against chronic liver injury induced by hepatotoxins such as carbon tetrachloride (CCl4); however, the protective mechanisms remain unclear. In the present study, a two-dimensional gel based proteomic approach was constructed to explore the mechanisms. Rats are injected with CCl4 twice a week for 4 weeks to induce liver fibrosis, and were fed laboratory chow plus 20% (w/w) of either corn oil or EVOO over the entire experimental period. Histological staining, MDA assay and fibrogenesis marker gene analysis illustrate that the CCl4-treated animals fed EVOO have a lower fibrosis and lipid peroxidation level in the liver than the corn oil fed group. The proteomic study indicates that the protein expression of thioredoxin domain-containing protein 12, peroxiredoxin-1, thiosulphate sulphurtransferase, calcium-binding protein 1, Annexin A2 and heat shock cognate 71 kDa protein are higher in livers from EVOO-fed rats with the CCl4 treatment compared with those from rats fed with corn oil, whereas the expression of COQ9, cAMP-dependent protein kinase type I-alpha regulatory subunit, phenylalanine hydroxylase and glycerate kinase are lower. Our findings confirmed the benefits of EVOO against chronic liver injury, which may be attributable to the antioxidant effects, hepatocellular function regulation and hepatic metabolism modification effects of EVOO.