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ObjectiveTo study the effect of isoflavones from Sojae Semen Praeparatum （ISSP） on lipid metabolism in atherosclerotic mice， and decipher the underlying mechanism via the peroxisome proliferator-activated receptor gamma/liver X receptor alpha/ATP-binding cassette transporter A1 （PPARγ/LXRα/ABCA1） signaling pathway. MethodFifty ApoE-/- mice were randomly assigned into the model group， western medicine （atorvastatin calcium， 3.03 mg·kg-1） group， and low-， medium-， and high-dose ISSP （2.5， 5， 10 mg·kg-1， respectively） groups， with 10 rats in each group. Atherosclerosis model mice were established by bilateral ovariectomy and feeding high-fat diet. Another 10 ApoE-/- mice receiving ovariectomy and high-fat diet were taken as the sham group. Some mice died of postoperative infection， and finally 6 mice were included in each group. One week after operation， each group was administrated with corresponding drugs or equivalent amount of normal saline. After 12 weeks， the levels of triglyceride （TG）， total cholesterol （TC）， high-density lipoprotein cholesterol （HDL-C）， low-density lipoprotein cholesterol （LDL-C）， and non-esterified fatty acids （NEFAs） in serum and liver tissue were measured. The levels of tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in serum were detected by enzyme-linked immunosorbent assay （ELISA）. Hematoxylin-eosin （HE） staining and oil red O staining were used for observation of aortic plaque formation and liver lipid deposition. The mRNA and protein levels of PPARγ， LXRα， ABCA1， and ATP-binding cassette transporter G1 （ABCG1） in liver were determined by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot. ResultCompared with the sham group， the modeling of atherosclerosis increased the aortic plaque area （P<0.01）， elevated the serum TC， TG， LDL-C， TNF-α， and IL-6 levels （P<0.01）， decreased the level of HDL-C （P<0.01）， increased the liver index （P<0.05） and the levels of TC， TG， and NEFAs in liver （P<0.01）， and caused obvious hepatic fat vacuoles and lipid deposition. In addition， the modeling down-regulated the mRNA levels of PPARγ， LXRα， ABCA1 in liver （P<0.05， P<0.01），and regulated the mRNA and protein levels of ABCG1（P<0.05， P<0.01）. Compared with the model group， atorvastatin calcium and middle-， high-dose ISSP reduced the serum TC， TG， LDL-C， TNF-α， and IL-6 levels （P<0.01）， decreased the liver index （P<0.01）， alleviated the liver fat vacuoles and lipid deposition， and increased the levels of TC， TG， and NEFAs in the liver （P<0.05， P<0.01）. Furthermore， they up-regulated the mRNA and protein levels of PPARγ， LXRα， ABCA1， and ABCG1 in the liver （P<0.05， P<0.01）. ConclusionISSP may regulate lipid metabolism through PPARγ/LXRα/ABCA1 signaling pathway to down-regulate the expression of inflammatory cytokines in serum and alleviate liver lipid deposition， thereby suppressing the formation of atherosclerotic plaque.
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Objective:To observe the expression levels of niemann-pick C1-like 1 (NPC1L1) and adenosine triphosphate-binding cassette transporters G8 (ABCG8) in intestine of hyperlipidemic model rats, in order to investigate the therapeutic mechanism of Shuangyu Tiaozhi decoction on hyperlipidemia. Method:A total of 40 SD rats were selected, including 8 for normal control group. The remaining 32 rats were used to establish hyperlipemic model. After modeling, the rats were randomly divided into the model group (equivalent normal saline), the high and low-dose Shuangyu Tiaozhi groups (15.6, 7.8 g·kg-1), and the Simvastatin group (4 mg·kg-1), with 8 in each group. They were given drugs by gavage for 8 weeks. The levels of total cholesterol (TC), triglyceride (TG) in serum and total cholesterol (TTC), free cholesterol (FTC) in liver of rats in each group were determined by biochemical and enzymatic methods. The morphological changes of liver were observed by hematoxylin-eosin (HE) staining, and the levels of expressions of NPC1L1, ABCG8 and liver X receptor-α (LXR-α) in intestine were detected by Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR) and Western blot. The expression of ABCG8 protein was determined by immunohistochemistry. Result:After successful replication of the hyperlipidemia model, the blood lipid level was abnormally increased, and the liver steatosis became obvious in the model group compared with the normal control group. The expression levels of NPC1L1, LXR-α and ABCG8 increased significantly (PPα were significantly down-regulated, but ABCG8 was obviously up-regulated in a dose-dependent manner (PPPPPPConclusion:Shuangyu Tiaozhi decoction can reduce the blood lipid level of hyperlipemic rat model by reducing the absorption of cholesterol. Its mechanism may be correlated with the down-regulation of NPC1L1 expression and the up-regulation of ABCG8 expression.
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Objective: To investigate the hypolipidemic effects of powder of Panax notoginseng (PPN) and explore its possible mechanism. Methods: Hyperlipidemic rats model was established, and orally given three dosages of PPN for 8 weeks. The levels of serum ALT, AST, TC, TG, and LDL-C were detected. The pathological changes of liver tissues were observed by H&E staining. Gene expressions of hepatic low density lipoprotein receptor (LDLR), SIRT1, and LXR-α were measured with RT-PCR analysis. Protein expression of SREBP-2 and SCAP was determined by Western blotting. Results: Three dosages of PPN significantly decreased serum ALT, AST, TC, TG, and LDL-C levels. Histological data indicated that PPN notably reduced liver injury and hepatic steatosis in hyperlipidemic rats. In molecular study, mRNA expression of hepatic LDLR and SIRT1 was up-regulated and LXR-α gene expression was down-regulated in PPN treated rats. Additionally, PPN significantly reduced protein expression of SREBP-2 and SCAP. Conclusion: The positive effect of PPN on hyperlipidemic rats may be related to the inhibition of cholesterol synthesis of PPN through the up-regulation of SIRT1 and down-regulation of LXR-α and SCAP/SREBP-2 signaling pathway. Additionally, PPN could up-regulate hepatic LDLR mRNA expression and improve uptake of LDL-C in circulation.
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Objective: To study the protective effects of Hemerocallis citrina total flavonoids (HCTF) on oxidative damage of liver cells HL-7702, and explore its possible mechanism. Methods: The liver cell damage model was induced by H2O2, and the proliferation of liver cells was examined by MTT assay, and the changes of ALT, LDH, and AST were dectected by ELISA assay, the levels of LXRα and FAS were determined by RT-PCR and Western blotting assay. Results: HCTF (5 and 10 μg/mL) could significantly improve the proliferation of liver cells (P < 0.01), the content of NO increased and the content of MDA decreased (P < 0.01 or 0.05), the activity of SOD increased (P < 0.05), the levels of mRNA, and protein of LXRα and FAS decreased (P <0.01 or 0.05). Conclusion: HCTF could inhibit the transcription and protein expression of LXRα and FAS through anti-oxidation, and repair the damage of HL-7702 liver cells caused by H2O2.
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Aim To develop an in vitro high throughput drug screening system based on reporter gene assay for identification of novel compounds with PXR, FXR and LXRα agonist activity. Methods The expressions of exogenous PXR, FXR and LXRαgene in HEK293, HepG2 and LS174T cells were examined by Real-Time quantity PCR. pSG5-hPXR and pGL3-XREM-CYP3A4, pEGFP-N3-hFXR and EcRE-TK-Luc, pCMX-FLAG-hLXRα and pGL3-XREM-CYP3A4 were cotransfected into cells and the optimal ratio of three plasmids was determined. The dose-response relationship between the positive drug and the fold induction was determined. The specificity of the model was ex-amined, and the repeatability was also determined by Z′ value. Results ① The PXR, FXR and LXRα mRNA expression in HEK293 cell is low among three different cells. ②reporter gene vector and expression plasmid ratio of 1∶ 1, 2∶ 1 and 2∶ 1 were proved to be suitable for highest relative luciferase activity for PXR, FXR or LXRα agonist screening model. ③ The relative luciferase activity was induced by Rif, CDCA or T0901317 in a dose-dependent manner. ④Only Rif, CDCA or T0901317 could significantly increase the relative luciferase activity in PXR,FXR or LXRα agonist screening model, no effect of other nuclear re-ceptors agonist was observed, and the values of Z′-factor for PXR, FXR and LXRαagonist screening model were 0. 58, 0. 66 and 0. 63, respectively. Conclusion An in vitro PXR, FXR and LXRα agonist high-throughput screening models are devel-oped with acceptable specificity and repeatability, and the mod-els can be used to screen PXR, FXR and LXRα agonist.
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Objective: To investigate the mechanism of lipid metabolism disorders in Kupffer cells (KCs) of non-alcoholic fatty liver disease (NAFLD) rats mediated by LXRα-SREBP-1c pathway and the interference of soothing liver and invigorating spleen recipe (SLISR) on it. Methods: SD male rats were randomly divided into five groups: normal, model, soothing liver recipe (SLR), invigorating spleen recipe (ISR), and soothing liver and invigorating spleen recipe (SLISR) groups. The rats in treatment groups were administered for 8 weeks. The liver tissue was stained with H&E and oil red O. The levels of hepatic lipid and blood lipid were measured by biochemical analyzer. KCs were isolated from the livers of rats to evaluate the expression of LXRα, SREBP-1C, and FAS mRNA by real-time fluorescence quantitative PCR tests; LXRα, SREBP-1C, and FAS proteins were measured by Western blotting. Results: The H&E and oil red O staining results showed that the model rats successfully reproduced typical pathogenetic and histopathological features of NAFLD. The levels of hepatic lipid and blood lipid in the model rats were dramatically increased. Compared with the model group, the values of hepatic lipid and blood lipid in the treatment groups were significantly ameliorated (P < 0.05, 0.01). The yields of purified KCs from each rat were 2×107-3×107. The viability of KCs was higher than 95%, with the purity over 90.18%. Compared with the model group, the expression of LXRα, SREBP-1C, and FAS mRNA and proteins was decreased in all treatment groups, especially in the SLR group (P < 0.05). Conclusion: SLISR may protect liver against injury included by lipid metabolism disorders in KCs through LXRα/SREBP-1c signaling pathway, which may be an important mechanism for the prevention and treatment of NAFLD.
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Aim To establish the hyperlipidemic model and ex-plore the mechanism of hypercholesterolemia in hamster. Meth-ods Hamsters were randomly divided into the control and model groups. The hamsters in the control group were fed with the standard chow and the model group were fed with the high fat di-et. Serum lipids and CYP7A1 activity were detected by enzymat-ic method. The molecular mechanism of cholesterol metabolism was investigated by real-time PCR. Results In comparison with the control group, the concentrations of serum TC, LDL-C, TG and hepatic TC, TG were significantly increased in the model group. The mechanism research showed that in hamsters fed with the high fat diet, the CYP7A1 activity and the mRNA expres-sions of hepatic LDL-R, SREBP-2, CYP7A1, LXRαwere down-regulated, the expression of hepatic FXR was up-regulated. Conclusion The hyperlipidemic model could be developed in hamsters fed with the high fat diet for 4 weeks. LDL-R, SREBP-2, CYP7A1, FXR and LXRαare the biomarkers of hypercholes-terolemia, and also the targets of hypolipidemic drugs.
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Purpose To examine the regulatory effect of recombinant human fibroblast growth factor-21 on the expression of liver X receptor α and glucose transporter protein 1 in the type 2 diabetes mellitus rats.Methods The rat models of type 2 diabetic mellitus were divided into four groups at random, ic. rhFGF-21 every day, after eight weeks of these treatment, Inspect the fasting blood glucose (FBG), fructosamine(FA), triglyceride(TG), T-cholesterol(TC), high density lipoprotein cholesterol(HDL-C) and low density lipoprotein cholesterol(LDL-C) of these rats, then detecting the mRNA expression of LXRα and GLUT1 by RT-PCR.Results (1) rhFGF-21 can reduce blood glucose steadily to near normal levels in diabetic rats. (2) The expression of LXRα and GLUT1 level was significantly higher in the rhFGF-21 treatment group than that in the model group. (3) rhFGF-21 megadoses and middle doses decreased FA, TG, TC,and LDL-C and elevated HDL-C.Conclusion rhFGF-21 could regulate the mRNA expression of LXRα and GLUT1 in diabetes rats, increase basal level glucose transport, then reduce blood glucose, improve lipid metabolize dysfunction.