Effects of high fat/high cholesterol diet on differentially expressed gene of the liver in treble genes mutant mice

AIM: To study the effects of dietary factor on liver gene expression profile in apoE-/-/LDLR-/-/Leprdb/db mice and atherogenesis. METHODS: The gene expression profile was determined by using cDNA microarray. Total plasma TC and TG level were measured with COD-PAP and GPO-PAP methods respectively. The morphological characters of the aorta were also observed. RESULTS: Among the 4000 target genes, 78 and 114 genes were up-and down-regulated, respectively, in treble genes mutants fed with high fat high cholesterol diet compared with that of regular chow littermates, including lipid metabolism, carbohydrate, cell skeleton and immune related genes. Atherogenic diet induced severe plasma hyperlipidemia even in the early stage and also accelerated atherogenesis in the treble genes mutant mice. CONCLUSION: The data suggest that atherogenic diet aggravates abnormal plasma lipid metabolism and induces severe hyperlipidemia, and atherogenesis in the treble genes mutant mice as well.     

Atorvastatin inhibits atherogenesis by RXRα-mediated depressing oxidative stress in STZ-induced diabetic ApoE-/- mice with fat-rich diet

AIM: To explore the effects of atorvastatin (Atorv) on atherosclerosis in streptozotocin (STZ)-induced diabetic apolipoprotein E knockout (ApoE-/-) mice with fat-rich diet and the possible mechanism. METHODS：C57 mice served as control. ApoE-/- mice (n=34) fed with high-fat diet were randomly divided into ApoE-/- group, STZ-ApoE-/- group and STZ-ApoE-/-+Atorv group. Intraperitoneal injection of streptozotocin was performed to create diabetic animal model. Blood glucose was determined by glucose oxidase method. Blood lipid levels were detected by enzymic method or selective homogeneous method. The plaque area in the thoracic aorta was measured by HE staining. The protein level of nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase subunit gp91phox in the thoracic aorta was determined by Western blotting. The levels of reactive oxygen species (ROS) in blood and thoracic aorta homogenates were detected by Fenton reaction and Griess reagent. Human umbilical vein endothelial cells (HUVECs) were isolated from healthy umbilical cords by collagenase I and cultured. ROS production was detected by flow cytometry. NADPH oxidase activity was measured using lucigenin assay.Effects of retinoid X receptor α (RXRα) on inhibition of oxidative stress by atorvastatin were evaluated by RNA interference and plasmid transfection. RESULTS：(1) Compared with C57 group, the plaque areas of the thoracic aorta in ApoE-/- group were increased. No difference of the fasting glucose between the 2 groups was observed. The levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), thoracic aorta gp91phox protein and ROS in blood and thoracic aorta homogenates were higher in ApoE-/- group than those in C57 group. (2) Compared with ApoE-/- group, the plaque areas of the thoracic aorta in STZ-ApoE-/- group were further enlarged ［(314.13±35.72) μm2 vs (215.88±34.19) μm2, P<0.05］. The levels of blood glucose, TG, TC and LDL-C, thoracic aorta gp91phox protein and ROS in blood and thoracic aorta homogenates were higher in STZ-ApoE-/- group than those in ApoE-/- group (P<0.05). (3) Compared with STZ-ApoE-/- group, the plaque areas of the thoracic aorta in STZ-ApoE-/- +Atorv group were reduced ［(217.47±24.56） μm2 vs （314.13±35.72） μm2, P<0.05］. The levels of blood glucose, LDL-C, TC, HDL-C and TG showed no significant difference between the 2 groups. Thoracic aorta gp91phox protein level and ROS production in blood and thoracic aorta homogenates were lower in STZ-ApoE-/- +Atorv group than those in STZ-ApoE-/- group (P<0.05). (4) High glucose-induced increases in NADPH oxidase activity and gp91phox expression were significantly inhibited by atorvastatin (10-6 mol/L) in HUVECs. The inhibitory effects of atorvastatin on high glucose-induced ROS production and NADPH oxidase activation were largely impaired when the cells were transfected with RXRα siRNA. However, the effect of atorvastatin was significantly strengthened when RXRα was over-expressed in the HUVECs transfected with RXRα plasmid. CONCLUSION：Atorvastatin inhibits atherogenesis by depressing high glucose-induced oxidative stress in diabetic ApoE-/- mice with fat-rich diet. The anti-oxidative stress effect of atorvastatin is mediated by RXRα.     

Expression of scavenger receptor B1 (SR-B1) in the liver of high fat and sugar diet-induced diabetic mice

AIM: To investigate serum lipid and the expression of SR-B1 in the livers of diabetic mice. METHODS: Ten normal diet, female C57BL/6J mice, fifteen high fat and sugar diet female C57BL/6J mice, five fed 8 weeks and ten fed 16 weeks were used in the experiment. Serum total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), insulin (INS) and the expression of SR-B1 in the livers were measured. RESULTS: 1. In the high fat and sugar diet mice, serum TC and FBG at 16 weeks were significantly higher than that in normal diet mice (P<0.05). 2. The expression of SR-B1 protein in the liver of high fat and sugar diet mice was the higher than that in normal mice, and the SR-B1 expression in the liver of the mouse fed 16 weeks was also higher than that fed 8 weeks. CONCLUSION: The expression of SR-B1 protein in the liver of type 2 diabetes mice is higher than that in normal mice, perhaps it is related to the decrease in serum HDL-C.     

Effects of ibrolipim against atherosclerosis in minipigs

AIM: To explore the application mechanism of NO-1886 (ibrolipim), a synthetic compound, improving dyslipidemia and inhibiting atherosclerosis in Guizhou minipigs fed with high fat/high sucrose diet. METHODS: Fifteen Chinese Guizhou minipigs were randomized into three groups with similar body weight ［(n=5 in normal control group (CD); n=5 in high fat/high sucrose group (HFSD); n=5 in high fat/high sucrose supplemented ibrolipim group （HFSD+ibrolipim)］. Blood samples were withdrawn from the eyehole sinus venosus of the animals at the end of each month after fasting overnight. The animals were sacrificed at the end of 8 months. The concentrations of cholesterol ester in plasma HDL were analyzed by HPLC. The aortic fatty streak-lesions were quantified following lipid staining with Sudan IV. Lipid droplets in liver were observed by Oil red O staining. RESULTS: Compared with CD, fasting plasma TC, TG and FFA levels of HFSD were elevated significantly. The aortic fatty streak-lesions were clearly presented in the animals’ aortas. The intima became rougher and thicker. A lot of lipoid foam cells migrated to regions of intima and smooth muscle cells, which associated with the injuries of internal elastic lamina. Extensive fat deposited in the liver were observed. Supplementing of 1.0% ibrolipim into high fat/high sucrose diet induced the decrease in plasma TG and FFA concentrations and an increase in plasma HDL-C concentration compared with HFSD. A little fat deposited in the liver were observed. CONCLUSION: ibrolipim prevents AS in high fat/high sucrose diet feeding minipigs through decreasing the plasma TG and elevating the plasma HDL-C.     

Differential proteomic analysis of liver in apoE/LDLR double-gene mutant mice

AIM: To comparatively study the differential expression of protein profiles of liver between double lipid metabolism genes mutant (apoE-/-/LDLR-/-) and wild type（WT）mice.The key proteins related to atherosclerosis and dysfunction of lipid metabolism were also characterized.METHODS: Two-dimensional gel electrophoresis and mass spectrometry were used to analyze the differential displayed proteomics of 5-week-old double-gene mutants and wild type mice fed a regular chow for 2 weeks.RESULTS: Approximately (928±15) spots and (1 017±50) spots were detected in apoE-/-/LDLR-/- mice (n=3) and WT mice livers (n=3),respectively.The average matched ratio was 78.7% and 83.2%.The differential expression analysis showed that the matched spots between apoE-/-/LDLR-/- mice and WT mice existed.Compared with the wild type,108 spots were not matched in apoE-/-/LDLR-/- mice.10 over expression spots (>5 fold) and 45 lower expression spots (>5 fold) were noted.Six significant differential proteins in gel were identified by LTQ-ESI,e.g.endoplasmin precursor,acidic leucin-rich nuclear phosphoprotein 32 family member A,serotransferrin precursor,stress-70 protein precursor,fibronectin precursor,complement C3 precursor,fibrinogen gamma polypeptide.CONCLUSION: The protein profile of apoE-/-/LDLR-/- mouse liver exhibits significant difference compared to that of WT mice.The results imply that lipid metabolism relative polygenetic mutation contributes to the alteration of mouse liver protein expression profile,especially that lipid metabolism related perhaps participates in dysfunction in lipid metabolism during atherogenesis.     

Effect of high fat diet on UCP2 mRNA expression in white adipose tissue of SR-A I/II gene knock-out mice

AIM:To observe the relationship between UCP2 mRNA expression in white adipose tissue and diet-induced obesity in SR-A I/II gene knock-out (SR-AⅠ/Ⅱ-/-) mice. METHODS:Fluorescent quantitative RT-PCR was used to detect UCP2 mRNA expression in mice epididymal white adipose tissue. The cellular morphological changes were analyzed by using image analysis. Serum TG, TC and LDL-C concentrations were measured by enzymatic determination. RESULTS:After fed with high fat diet for 12 weeks, average body weight of SR-A I/II-/- mice was much higher than that of wild type (SR-A I/II+/+) control mice (P<0.01), as well as the serum lipid (TG, TC, LDL-C) levels, epididymal fat pad weight, adipocyte area and diameter. UCP2 mRNA expression in white adipose tissue in SR-A I/II-/- mice was significant lower than that in SR-A I/II+/+ control mice (P<0.01). CONCLUSION:Abnormal UCP2 mRNA expression may be associated with SR-A I/II-/- mice susceptive to diet-induced obesity.     

Effect of polygonum cuspidatum and hawthorn on anti-atherosclerosis unstable plaque

AIM: To investigate the effect of detoxifying herbs polygonum cuspidatum, and hawthorn, herb of promoting blood flow, on pathologic morphology and inflammatory factors in apolipoprotein E gene knockout mice, in order to approach the possible regulatory mechanism of polygonum cuspidatum and hawthorn for treating artherosclerosis (AS) unstable plaque. METHODS: The animals were divided into 7 groups (12 mice in every group). The ApoE (-/-) mice fed with high fat diet were divided into polygonum cuspidatum group, hawthorn group, polygonum cuspidatum + hawthorn group, Xuezhikang group and high fat diet model group. Moreover, ApoE (-/-) mice fed with normal diet (normal diet group) and C57BL/6J mice fed with normal diet (normal control group) were set up. After intragastric administration for 17 weeks, serum hs-CRP was detected, aorta structure was observed under light microscope and NF-κB protein expression was determined by immunohistochemistry. RESULTS: The pathological change of AS in aorta in all groups fed with high fat diet and normal diet group were observed with different degree. The changes of aortic lesion in all treatment groups were reduced. The levels of NF-κB and hs-CRP in high fat diet group were significant higher than those in normal control group and normal diet group. Serum NF-κB and hs-CRP levels decreased in every treatment group, which were significant different from those in high fat diet model group (P<0.01). Among them, the changes in polygonum cuspidatum and hawthorn groups were the best. CONCLUSION: Chinese herbs of polygonum cuspidatum and hawthorn reduce inflammatory factors NF-κB and hs-CRP expression and play a role in anti-AS formation.     

High-cholesterol diet with or without corn oil for establishing atherosclerotic model in rabbits

AIM：To compare the reliability and plaque area between using high-cholesterol diet and high-cholesterol diet with corn oil to establish a rabbit atherosclerotic model. METHODS：Eighteen New Zealand rabbits were randomly divided into 3 groups (6 rabbits each): normal diet group (group C), high-cholesterol diet group (group H1) and high-cholesterol diet containing 6% corn oil group (group H2). All rabbits were fed for 12 weeks, and their body mea-sured was weighed at the end of every weeks. The serum levels of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and triglyceride (TG) were measured by automatic chemistry analyzer at 0 week and 12 weeks. At the end of 12 weeks, the thoracic aorta of 8-cm length since aortic root was isolated from the rabbit after anesthesia, and stained with Sudan IV or oil red O to verify the existence of plaque. The percentage of plaque area (PA/IA) in the intima area was further calculated by ImageJ2x software. RESULTS：At the end of 12-week feeding, the serum levels of HDL-C, LDL-C and TC in both group H1 and group H2 were significantly higher than those in group C, and serum TG in group H2 was significantly higher than that in group C. Serum HDL-C in group H2 was significantly higher than that in group H1, but no significant difference of serum LDL-C, TC and TG between group H1 and group H2 was found. There was no plaque in the intima in group C, and plaques were observed in the intima of all rabbits in group H1 and group H2. Rabbit atherosclerotic models in both group H1 and group H2 were established with a success rate of 100%. The values of PA/IA in group H1 ［(49.74±18.78)%］ and group H2 ［(56.95±26.74)%］ were both significantly higher than that in group C (0%), and no significant difference of PA/IA between group H1 and group H2 was observed. CONCLUSION：High-cholesterol diet with or without corn oil can establish a rabbit atherosclerotic model with a success rate of 100% after 12-week feeding, and the percentage of plaque area in the total aortic intimal area is not different in the 2 feeding methods.     

Effects of Sini decoction on atherosclerosis and ceramide content of aorta in rabbits

AIM:To observe the effects of Sini decoction on atherosclerosis(AS) and ceramide content of aorta in rabbits. METHODS:28 rabbits were randomly divided into three groups. Control group was fed with a normal diet; High cholesterol group was fed 1% cholesterol and 5% fat diet; Sini decotion+ high cholesterol group was fed 1% cholesterol and 5% fat diet plus Sini decotion (4.2 g·kg^-1·d^-1). At the end of study, the plaque area were measured, the atorta ceramide and cell apoptosis were also detected. RESULTS:Sini decotion diminished lipid plaque area on the aortic endothelium, reduced the levels of aorta ceramide and the apoptosis index. CONCLUSION:Sini decoction has an inhibitory effect on AS, the mechanism may be that Sini decotion reduces concentration of ceramide in aorta.     

农杆菌介导的CBF1基因对松南结缕草的遗传转化

CBF1（C-repeat/dehydration-responsive element binding factors 1）基因为来源于拟南芥的一类与干旱、高盐及低温耐性有关的转录因子基因。松南结缕草（Zoysia sp.）是本实验室育成的形态特征介于日本结缕草与沟叶结缕草之间的一种中型结缕划，在长江以南地区广泛种植。     

Retarding effect of simvastatin on artery remodeling induced by high-salt and high-fat diet in rats

AIM: To investigate the effect of simvastatin intervention on the changes of blood pressure, serum lipid fluctuation and aortic configuration induced by high-sodium and high-fat diet in rats. METHODS: Sixty adult male SD rats were randomly divided into 5 groups (n=12): control (N)group, high salt (S)group, high fat (F) group, high salt+ high fat (SF) group and high salt+high fat + simvastatin (T) group. After fed for 16 weeks, the rats were subject to determine blood pressures and serum concentrations of triglycerides (TG),total cholesterol(TC) and soluble CD40 ligand (sCD40L). The expression of CD40/CD40L in the root of ascending aorta was detected by immunohistochemical method. The thickness of intima media in the ascending aorta as well as the ratio of lumen area/total vascular area were measured and calculated after HE staining. RESULTS: In S group, F group and SF group, systolic blood pressure was significantly higher than that in N group (P<0.01). Systolic blood pressure in T group were slightly higher than that in N group with statistical significance and significantly lower than that in SF group. The serum concentrations of TG and TC in F group and SF group were significantly higher than those in N group and T group (P<0.01), and no significant difference among S group, N group and T group was observed. In S group, F group and SF group, the serum concentrations of sCD40L were higher than that in N group and T group (P<0.05), meanwhile that in SF group was also higher than that in S group and F group (P<0.05). However, no significant difference of sCD40L concentration between S group and F group as well as N group and T group was observed. The expression of CD40/CD40L in the ascending aorta in S group, F group and SF group was higher than that in N group and T group (P<0.05), and that in SF group was also higher than that in S group and F group (P<0.05).No significant difference of CD40/CD40L expression between S group and F group as well as N group and T group was observed. The thickness of intima media in S group, F group and SF group was significantly thicker than that in N group (P<0.01), and no significant difference of the intima media thickness between T group and N group was observed. The ratio of lumen area/total vascular area in S group, F group and SF group was smaller than that in N group (P<0.05), and no significant difference of the ratio between T group and N group was found. CONCLUSION: Feeding high-fat and high-salt diet leads to blood pressure elevation, induces atherosclerosis, increases serum concentration of sCD40L and enhances the expression of CD40/CD40L in arterial tissues. The combination of the stimuli has stronger effect than a single factor. Statins protect the arterial tissues against atherosclerosis by decreasing the level of serum sCD40L and inhibiting the arterial expression of CD40/CD40L.     

Effect of simvastatin on expression of integrin-linked kinase and renal tubulointerstitium injury in rats induced by high fat diet

AIM: To explore the effect of simvastatin on expression of integrin-linked kinase (ILK) and the injury of renal tubulointerstitium in the rats induced by high fat diet. METHODS: Fifty-four 6-8 week-old female Wistar rats were randomly assigned to the following three groups: high fat diet group, simvastatin group (rats were fed with high fat diet plus 10 mg·kg-1·d-1 simvastatin) and control group. Six rats in each group were sacrificed at 4th week, 10th week, and the others at 20th week. The injury of renal tubulointerstitium was observed under microscope with HE staining and the expression of renal ILK was determined by Western blotting analysis and immunohistochemistry. Levels of total cholesterol (TC) and triglyceride (TG) in serum were measured by enzymatic colormetric methods. RESULTS: The serum TC and TG levels and the expression of renal ILK significantly increased in both high-fat diet group and simvastatin group, compared to control group at 4th week, reaching a maximum at 20th week (P<0.01). Tubulointerstitium injuries including vacuolar degeneration, syncytial change, clody swelling, necrosis and atrophy of renal tubular epithelial cells, thinning of tubal wall, lumens compensational expansion or even abolition, and inflammatory cell infiltration, interstitial fibrosis were found in both high fat diet group and simvastatin group, compared to control group at 4th week, worsened to a maximum at 20th week. However, all of these ameliorated in simvastatin group, compared to high fat diet group at each time point. CONCLUSION: The results indicate that high-fat diet induces significant lesion of renal tubulointerstitium and increased expression of renal ILK. Simvastatin may play an important role in protecting against tubulointerstitium injury induced by hyperlipoidemia by down-regulating the expression of renal ILK.     

Regulatory effect of RXR/VDR agonists on atherosclerosis and NF-κB expression in diabetic ApoE knockout mice

AIM：To explore the effect of retinoid X receptor (RXR) agonist bexarotene (Bex) and vitamin D receptor (VDR) agonist calcitriol (Cal) on the expression of nuclear factor-kappa B (NF-κB) and the development of atherosclerosis in streptozotocin-induced diabetic apolipoprotein E knockout (STZ-ApoE-/-) mice. METHODS：Male mice were treated for 12 weeks as follows: (1) C57+vehicle; (2) ApoE-/-+vehicle; (3) STZ-ApoE-/-+vehicle; (4) STZ-ApoE-/-+Bex (10 mg·kg-1·d-1); (5) STZ-ApoE-/-+Cal (10 μg/kg, twice a week); (6) STZ-ApoE-/-+Bex (10 mg·kg-1·d-1)+Cal (10 μg/kg, twice a week). Intraperitoneal injection of STZ was performed to establish the diabetic animal model. Western blotting and immunohistochemical method was used to detect NF-κB level in the thoracic aorta. Plaque area in the thoracic aorta was measured using HE staining. RESULTS：Compared with the C57 mice, the fasting blood glucose in the ApoE-/- mice was not remarkably changed. The levels of total cholesterol (TC) and low-density lipoprotein (LDL) were greatly increased. The fasting blood glucose and lipid levels in STZ-ApoE-/-group were much higher than those in ApoE-/- group. Compared with STZ-ApoE-/- group, the fasting blood glucose and lipid levels in Bex group and Cal group were not significantly changed. Compared with the C57 mice, the protein expression of NF-κB in the ApoE-/- mice and the STZ-ApoE-/- mice was remarkably increased. Compared with STZ-ApoE-/- group, the levels of NF-κB in Bex group, Cal group and combination group were greatly decreased.Compared with STZ-ApoE-/- group, the thoracic artery plaque areas in Bex group and Cal group were inhibited (both P<005). Compared with Bex group, the plaque area of the thoracic artery in combination group was significantly decreased (P<005). CONCLUSION：Bexarotene or calcitriol decreases the development of atherosclerosis in streptozotocin-induced diabetic ApoE-/- mice. Bexarotene combined with calcitriol affords greater protection than monotherapy. The mechanism may be involved in down-regulating the expression of NF-κB.     

Role of Huoxue Jiangzhi Recipe in preventing and treating fatty liver in mice

AIM: To explore the role of Huoxue Jiangzhi Recipe in preventing and treating fatty liver in mice and its underlying mechanisms. METHODS: Healthy Kunming mice were fed with high-fat diet and treated intragastrically with different doses of Huoxue Jiangzhi Recipe (compound of ginseng, panax notoginseng and rhizoma gastrodiae, named as GST) for 2 weeks. The levels of blood lipids and triglyceride (TG) in hepatic tissues were measured. Meanwhile, liver index and hepatic pathology were observed. The optimized dosage of Huoxue Jiangzhi Recipe was determined by the experiments. The mice were divided into normal control group (NC group, fed with normal diet) and model group (fed with high-fat diet). The model mice were subdivided into 3 subgroups 12 weeks later: HF group (fed continuously with high-fat diet), ND group (fed with normal diet), GSL group (fed with normal diet and treated intragastrically with GSL). The mice in NC, HF and ND groups were given distilled water by gastric perfusion. Two weeks later, all mice were killed, and blood was collected for measuring serum total cholesterol (TC),TG,high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C) contents, hepatic TC, TG, malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity were detected. Moreover, liver index and hepatic pathology were also observed. The mRNA expression of peroxisome proliferator-activated receptor alpha (PPARα) and cytochrome-P450 2E1 (CYP2E1) in the liver was examined by RT-PCR. RESULTS: GST significantly decreased serum lipid, hepatic lipid and MDA levels and elevated SOD activity. Furthermore, GST markedly reduced liver index, improved hepatic adipose infiltration, increased PPARα mRNA expression and inhibited CYP2E1 mRNA expression. CONCLUSION: GST is effective in the treatment of fatty liver in mice by up-regulating PPARα, thus reducing serum and hepatic TG levels, down-regulating CYP2E1 and inhibiting lipid peroxidation.     

Protective effect of adiponectin on glucose and lipid metabolism by suppressing MHCⅡ expression

AIM: To investigate whether the protective effect of adiponectin on glucose and lipid metabolism is achieved through down-regulating major histocompatibility complex class Ⅱ (MHCⅡ) in the adipose tissue. METHODS: Adiponectin knockout (KO) mice and C57BL/6(WT) mice were fed with high-fat diet and standard diet for 24 weeks, respectively. The body weight, fasting blood glucose (FBG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), hepatic histology, and class Ⅱ trans-activator (CⅡTA), histocompatibility 2 class Ⅱ antigen E beta (H2-Eb1) and cluster of differentiation 74(CD74) mRNA and MHC Ⅱ protein levels in adipose tissue were measured at sacrifice. siRNA targeting MHC Ⅱ and overexpression vector was used in 3T3-L1 cells to explore the effect of adiponectin on the protein level of MHCⅡ. RESULTS: The levels of body weight, FBG, FINS, HOMA-IR, TC, TG, LDL-C, hepatic steatosis, CⅡTA, H2-Eb1 and CD74 mRNA expression, and MHCⅡ protein expression in the KO mice were higher than those in the WT mice that fed with high-fat diet or standard diet. In 3T3-L1 cells, inhibition of adiponectin reversed MHC Ⅱ protein level induced by specific siRNA. The expression of MHC Ⅱ in adipocytes decreased after adiponectin was overexpressed. CONCLUSION: Adiponectin improves glucose and lipid metabolism through suppressing the expression of MHCⅡ in the adipose tissue.     

Effect of insulin resistance on fatty liver in high-fat diet-fed mice

AIM: To study the influence of insulin resistance on fatty liver in the mice fed with high-fat diet (HFD).METHODS: Male 8-week-old C57BL/6J mice were randomly divided into HFD group (with 60% calories by high saturated fatty acid) and control group (with chow diet).The mice in both groups were fed for 12 weeks. The body weight, liver weight, serum triglyceride (TG) and total cholesterol (TC), and blood glucose and insulin levels were measured. Hyperinsulinemic euglycemic clamp experiment was applied to reflect insulin sensitivity. The lipid deposition in the liver was analyzed by HE staining, Sudan IV staining and measurement of liver fat content. The phosphorylation levels of IRS1 and Akt, and the protein levels of SREBP-1 and FAS were determined by Western blot to reflect the activities of insulin signaling and lipid synthesis.RESULTS: Compared with control group, the body weight and liver weight were significantly increased in HFD group. TG and TC contents in serum and liver tissues were remarkably increased in HFD group. High-fat diet induced insulin resistance, as evidenced by increased serum insulin levels, reduced glucose infusion rate and decreases in IRS1 and Akt phosphorylation levels. In livers of HFD group, HE staining showed that the cytoplasm of hepatocytes was filled with vacuoles. Sudan IV staining also displayed that many different sizes of red lipid drops existed in the hepatocytes, and the protein levels of SREBP-1 and FAS were significantly increased. In primary normal hepatocytes with exogenous oleic acid intervention for 48 h, the phosphorylation levels of IRS1 and Akt were reduced, and the protein expression of SREBP-1 and FAS was significantly increased in a dose-dependent manner.CONCLUSION: Feeding with HFD leads to insulin resistance, resulting in activation of lipid synthesis and accumulation of lipid deposition in the liver, thus inducing fatty liver.     

Influence of Salvia miltiorrhiza injection on lipid and ICAM-1 expression in rats with atherosclerosis

AIM: To study the effect of Salvia miltiorrhiza injection on rat atherosclerosis (AS), and elucidate the possible mechanism. METHODS: Wistar rats were fed with fat-rich diet and high dose of vitamin D₃ to induce AS, then treated with Salvia miltiorrhiza injection. Concentrations of triglyceride (TG) and total cholesterol (TC) in serum were measured by automatic serum biochemical assay. The level of ICAM-1 protein and mRNA were determined by Western blot and RT-PCR. RESULTS: Compared with the AS model group, the levels of TG and TC in serum were significantly lower in Salvia miltiorrhiza injection group (P<0.05). Western blot and RT-PCR showed that the level of ICAM-1 protein and mRNA were decreased in Salvia miltiorrhiza injection group compared with AS group. CONCLUSION: Salvia miltiorrhiza injection decreased blood lipid and reduced the ICAM-1 gene expression in rats with atherosclerosis.     

Effects of Retinervus luffae fructus on serum lipid level in experimental hyperlipidemia rats

AIM: To investigate effects of Retinervus luffae fructus (RLF) on level of serum lipid and body weight in hyperlipidemia rats. METHODS: Thirty-two male SD rats were randomly divided into four groups: control group (A), hyperlipidemia group (B), hyperlipidemia + RLF group (C), RLF group (D). Both group A and C were fed normal diet every day, while group B and group D fed high fat diet. Meanwhile, group C and D were administered with RLF solution at the dose of 10 mL/kg, respectively for 14 days, while group A and B were administered with drinking water. RESULTS: (1) At the end of experiment, a significant reduction was found in the levels of serum total cholesterol (TC) and triglyceride (TG) of group C animals treated with RLF solution; (2) The levels of serum TC of group D was progressively decreased compared to the level of serum TC at the beginning of experiment; (3) The level of high-density lipoprotein cholesterol (HDL-C) of group C remained unaltered 8d after treatment with RLF solution; (4) The body weight in group C was obviously lower than that in group B. CONCLUSION: RLF had an obvious hypolipidemic effect on hyperlipidemia rats. It can inhibit the decrease in the HDL-C and the increase of body weight in rats.