Improvement of insulin sensitivity by osteocalcin inhibits inflammation in the adipose tissue of obese mice

AIM: To explore the improving effect of osteocalcin on obesity-related insulin resistance and inflammation in the adipose tissue of obese mice.METHODS: The C57BL/6 mice were fed with high-fat diet for 12 weeks to obtain obese mice. Osteocalcin (30 ng/kg or 3 ng/kg) and saline solution (control) were intraperitoneally injected for other 4 weeks. The fat mass, body weight, serum triglycerides and serum free fatty acid were analyzed. Intraperitoneal glucose tolerance test and insulin tolerance test were carried out. Macrophage infiltration degree in the adipose tissue was observed by immunohistochemical staining. The mRNA expression of monocyte chemotactic protein-1 (MCP-1) and CD68 was detected by real-time fluorescence quantitative PCR.RESULTS: Osteocalcin (30 ng/kg or 3 ng/kg) treatment for 4 weeks significantly reduced the body weight, fat mass and insulin level, and improved abnormal glucose tolerance and insulin resistance in the obese mice. Moreover, the macrophage infiltration decreased, and the mRNA expression of MCP-1 and CD68 was down-regulated in the adipose tissue of obese mice treated with osteocalcin at 30 ng/kg.CONCLUSION: Osteocalcin at 30 ng/kg significantly reduces body weight and fat mass, and attenuates the severity of insulin resistance through down-regulating the mRNA expression of MCP-1 and CD68 and inbihiting macrophage infiltration in the adipose tissue of obese mice induced by high-fat diet.     

Up-regulation of CD36 induced by casein-induced inflammation promotes renal injury in mice

AIM: To investigate the role of CD36 in casein-induced mouse renal injury.METHODS: Eight-week-old male C57BL/6J mice and CD36 knockout (CD36KO) mice were randomly divided into C57BL/6J saline injection group, C57BL/6J casein injection group and CD36KO casein injection group (n=8 in each group). After 14 weeks of treatment with high-fat diet, the mouse serum, 24 h urine and kidney tissue samples were collected for analysis. The serum content of tumor necrosis factor-α (TNF-α) was measured by ELISA. The renal function markers in the serum and urine were determined by an automatic biochemical analyzer. The pathological changes of the kidney were observed by HE staining and Masson staining. The expression of CD36 and cytokines/chemokines (TNF-α, IL-6 and MCP-1) at mRNA and protein levels in the renal tissues were determined by real-time PCR and Western blot. The content of tissue hydrogen peroxide (H₂O₂) was measured by a commercial kit. The protein levels of Nrf2 and TGF-β1 in the renal tissues were measured by immunohistochemical staining.RESULTS: Compared with saline injection group, casein injection increased the level of TNF-α in the serum and in the kidney tissues of C57BL/6J mice (P<0.05), suggesting that casein injection successfully induced chronic inflammation in C57BL/6J mice. Casein injection also promoted the protein expression of CD36 and TGF-β1 in the renal tissues of the C57BL/6J mice, accompanied with glomerular sclerosis, proteinuria, increased serum creatinine content, increased H₂O₂ content, and decreased Nrf2 protein level and the ability of antioxidant in the kidneys (P<0.05). Furthermore, CD36 deficiency protected the mice from casein-induced renal injury, as evidenced by improved kidney pathological changes and decreased proteinuria. The content of H₂O₂ in the kidneys of casein-treated CD36 knockout mice was also lower than that in casein-treated C57BL/6J mice.CONCLUSION: Inflammatory responses promote the oxidative stress and renal injury in a CD36-dependent manner.     

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.     

Anthocyanins attenuates hepatic fibrosis and inflammation in non-alcoho-lic fatty liver disease mice

AIM:To explore the therapeutic effect of anthocyanins from Fructus Acanthophorae on high-fat diet-induced non-alcoholic fatty liver disease (NAFLD) in mice and the potential mechanism. METHODS:NAFLD mouse model was established by high-fat diet, and interferred with anthocyanins. The liver weight, and serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglyceride (TG), total cholesterol (TC) and low-density li-poprotein cholesterol (LDL-C) were measured. The liver tissues were staining with HE, Oil Red O and Masson's trichrome. The protein levels of inflammatory factors tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-10 in the liver tissues were determined by Western blot. The liver macrophage, white blood cell and mononuclear cell infiltration was detected by immunohistochemical method. The chemokines CCL7 and MCP-1 were also measured by immunohistochemical method. RESULTS:Anthocyanins significantly inhibited the increases in the liver weight, ALT, AST, TG, TC and LDL-C induced by high-fat diet. Anthocyanins attenuated the liver fibrosis and inflammatory cell infiltration caused by high-fat diet, and reduced the levels of inflammatory factors TNF-α, IL-1β, IL-6, IL-10 and inflammatory chemokines CCL7 and MCP-1 in the liver tissues. CONCLUSION:Anthocyanins significantly alleviate non-alcoholic fatty liver disease caused by high-fat diet though reducing inflammatory factors, inflammatory cell infiltration and inflammatory chemokines.     

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.     

Inflammatory cytokines up-regulate FAT/CD36 expression in renal cells loaded by fatty acids

AIM: To investigate the effects of inflammatory cytokines on the expression of fatty acid transporter (FAT/CD36) in renal cells loaded by fatty acids. METHODS: Human mesangial cells (HMCs) and renal tubular epithelial HK-2 cells were treated with palmitate at concentrations of 0 mmol/L, 0.02 mmol/L, 0.04 mmol/L, 0.08 mmol/L, 0.16 mmol/L and 0.32 mmol/L for 24 h. The expression of FAT/CD36 at mRNA and protein levels was detected by real-time PCR and Western blotting,respectively. The renal cells were treated with palmitate at concentration of 0.04 mmol/L combined with TNF-α (25 μg/L) or IL-6 (20 μg/L) for 24 h. The effect of inflammatory cytokines on the mRNA and protein levels of FAT/CD36 in the renal cells was also investigated. Oil red O staining was used to determine the intracellular lipid droplet formation. The intracellular triglyceride (TG) and free fatty acid (FFA) were measured by enzymic assay and ELISA, respectively. RESULTS: Palmitate loading dose-dependently increased the expression of FAT/CD36 at mRNA and protein levels in both HMCs and HK-2 cells. The inflammatory cytokines further increased the expression of FAT/CD36 at mRNA and protein levels in both cells loaded by palmitate. Oil red O staining, TG detection and FFA assay showed that the inflammatory cytokines increased intracellular lipid levels in both HMCs and HK-2 cells. CONCLUSION: Inflammatory cytokines up-regulate the expression of FAT/CD36 in renal cells loaded by fatty acids and exacerbate the intracellular lipid accumulation.     

Effect of electroacupuncture in different intensities on endoplasmic reti-culum stress in adipose tissues from high-fat diet-induced obese rats

AIM: To investigate the effect of electroacupuncture (EA) in different intensities on unfolded protein response (UPR) signaling pathway in adipose tissues from high-fat diet-induced obese rats. METHODS: Sixty SD rats were randomly divided into 2 groups: common diet group (n=10) and high-fat diet group (n=50). Thirty obese rats in high-fat diet group were chosen and divided into high-fat diet group, 5 mA EA group and 1 mA EA group (n=10 each). EA at frequency of 20 Hz and intensities of 5 mA or 1 mA was applied to ST 36 and SP 6 for 15 min once daily for 2 weeks. The body weight was detected once a week. The expression of p-PERK and CHOP/GADD153 in epididymal adipose tissues was determined by Western blotting. The content of Bcl-2 and caspase-12 in the adipose tissues was measured by ELISA. RESULTS: After EA, the body weight and the expression of p-PERK and CHOP/GADD153 in obese rats were significantly decreased (P<0.01 or P<0.05). The rats in 5 mA EA group exhibited a better improvement on the protein expression than the rats in 1 mA EA group.CONCLUSION: EA has a beneficial regulatory effect on the rats with simple obesity. Moreover, the EA density of 5 mA is superior to 1 mA.     

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.     

Role of Api6 in lung inflammation induced by high fat/cholesterol food in C57BL/6J mice

AIM：To investigate the function of apoptosis inhibitor 6 (Api6) in lung inflammation induced by high-fat high-cholesterol diet (HFD/HCD) in male C57BL/6J mice. METHODS：Male C57BL/6J mice (6~8 weeks old) were randomly divided into 2 groups and treated with regular diet and HFD/HCD, respectively. After 16 weeks of feeding, the lung tissues were collected and the pulmonary inflammatory status was determined by immunohistochemistry and ELISA. The mRNA and protein expression levels of Api6 were determined by real-time PCR and Western blotting. The apoptotic rate of bronchioalveolar lavage cells was examined by flow cytometry. RAW264.7 cells were cultured in vitro and the apoptosis induced by oxidized low-density lipoprotein (oxLDL) was detected by flow cytometry. RESULTS：Accumulation of macrophages and increases in both tumor necrosis factor α and monocyte chemoattractant protein 1 were observed in the lung tissues of 16-week HFD/HCD-fed C57BL/6J mice. Compared with the regular diet-fed mice, the expression of Api6 at mRNA and protein levels in the lung tissues was highly increased in the HFD/HCD-fed mice (P<0.01). Meanwhile, the apoptotic rate of bronchioalveolar lavage macrophages from the HFD/HCD-fed mice was highly inhibited (P<0.01). In vitro, 500 μg/L recombinant Api6 significantly inhibited the apoptosis of RAW264.7 cells induced by oxLDL (P<0.05). CONCLUSION：HFD/HCD feeding results in the accumulation of macrophages in the lung of C57BL/6J mice, which may partly due to the increased expression of Api6 and its anti-apoptotic role in macrophages.     

Expression of CXC chemokine receptor 7 in atherosclerotic ApoE-deficient mice and therapeutic impact by atorvastatin

AIM: To evaluate the expression level of CXC chemokine receptor 7 (CXCR7) in atherosclerotic apolipoprotein E-deficient (ApoE^-/-) mice induced by high-fat diet (HFD) and the effects of atorvastatin on it. METHODS: ApoE^-/- male mice (8-week-old) were used and were randomly divided into 3 groups following 1-week normal rodent diet: normal diet control (NDC) group, HFD group and HFD+statins (HFD+Sat) group. HE staining and oil red O staining were used to observe the atherosclerotic lesion burdens in the aortas. The expression of CXCR7 on the aortas was detected by Western blot and immunohistochemistry. The expression of Akt and endothelial nitric oxide synthase (eNOS) in the aorta was determined by Western blot.RESULTS: Few lesions were found in the aortas in NDC group. Apparent atherosclerotic plaque burdens were seen in HFD group and HFD+Sat group, while the atherosclerotic plaque burdens in HFD+Sat group were notably reduced compared with HFD group. The protein levels of CXCR7, eNOS and Akt in aorta in HFD group and HFD+Sat group were significantly decreased compared with NDC group, while those in HFD+Sat group were increased compared with HFD group. The protein level of p-eNOS in the aorta and the concentration of NO in the plasma in HFD group were decreased compared with NDC group and HFD+Sat group. CONCLUSION: In ApoE^-/- mice, HFD increases the lipid level and promotes the development of atherosclerosis by downregulating the expression of CXCR7, Akt and eNOS. Atorvastatin reverses the above effect of hypercholesterolemia on the expression of CXCR7, Akt and eNOS, thus playing the role in treating atherosclerosis.     

Radix Pseudostellariae polysaccharide attenuates high fat diet induced hepatic insulin resistance in mice

AIM: To study the role of Radix Pseudostellariae polysaccharide (RPP) in hepatic insulin resistance.METHODS: Six-week-old C57BL/6J mice were randomly divided into low-fat diet (LFD) control group and high-fat diet (HFD) model group. After 16 weeks, intraperitoneal pyruvate tolerance test (IPPTT) was performed to determine the establishment of the HFD-induced hepatic insulin resistance model. HFD containing RPP (500 mg/kg) was given for 4 consecutive weeks. IPPTT, liver malondialdehyde (MDA) level and liver mitochondrial MDA level were measured. The protein levels of p-AKT (Ser473/Thr308), p-AMPK, nuclear factor E2-related factor 2 (Nrf2), NQO1 and IκBα in the liver tissues were measured by Western blot.RESULTS: After administration of RPP, a significant reduction in the levels of blood glucose and hepatic mitochondrial MDA was observed. The levels of p-AKT (Ser473/Thr308) and p-AMPK were significantly elevated in the liver tissues. The hepatic IκBα levels were up-regulated. RPP also enhanced the expression of Nrf2 system-regulated proteins NQO1 and HO-1 in the liver tissues.CONCLUSION: Radix Pseudostellariae polysaccharides effectively reduce HFD-induced hepatic insulin resistance in C57BL/6J mice and improves liver glucose metabolism by ameliorating HFD-impaired hepatic transduction of insulin signaling, activating Nrf2-associated signaling and inhibiting the expression of inflammatory signaling proteins.     

Mechanism of hepatic insulin resistance induced by high-fat diet

AIM: To observed the relationship between oxidative stress and development of insulin resistance in hepatic tissues of Sprague dawley(SD) rats by analyzing reactive oxygen species(ROS) level and NADPH oxidase 3(NOX3) expression in livers. METHODS: Four-week-old male SD rats were fed with high-fat diet containing 20% fat and 20% sucrose for 12 weeks to induce insulin resistance. Plasma insulin level was detected by radioimmunoassay. The content of liver intracellular glycogen was measured using a glycogen assay kit. ROS generation in the liver tissues was assessed by dihydroethidium(DHE) fluorescence. The expression of NOX3 was determined by Western blotting.RESULTS: After 12 weeks of high-fat diet feeding, the content of blood glucose was increased but still maintained in normal level in the rats. However, the index of insulin sensitivity obviously decreased. Hepatic glycogen content in the rats fed with high-fat diet was significantly decreased, indicating that insulin resistance developed. Enhanced ROS production in hepatic tissues of the rats fed with high-fat diet was observed. Importantly, the expression of NOX3 in the liver was up-regulated in response to high-fat diet in vivo.CONCLUSION: High-fat diet feeding decreases insulin sensitivity, enhances ROS level and NOX3 expression, and reduces glycogen content in the livers.     

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.     

Lipid-induced p62dok up-regulation enhances hepatic gluconeogenesis

AIM:To investigate the potential role of p62^dok in the regulation of hepatic gluconeogenesis. METHODS:The expression of p62^dok, insulin signaling transduction, and hepatic gluconeogenesis were investigated in the liver tissues of mice treated with high-fat diet(HFD) and in cultured mouse hepatocytes treated with free fatty acid(FFA). The experiments of gene silencing and overexpression were conducted to observe the effects of p62^dok on insulin signal transduction and hepatic gluconeogenesis in cultured mouse hepatocytes. Western blotting was used to detect the protein levels and the phosphorylation statue. RESULTS:The increased p62^dok levels were found in the liver tissues from HFD-treated mice and FFA-treated hepatocytes. Meanwhile, phosphorylation of Akt and forkhead box O1 protein(FoxO1) was were decreased and the expression of glucose-6-phosphatase(G6Pase) and phosphoenolpyruvate carboxykinase(PEPCK) was increased. Silencing of p62^dok in cultured hepatocytes treated with FFA induced the increase in phosphorylation of Akt and FoxO1, and decrease in the protein levels of G6Pase and PEPCK. CONCLUSION:Up-regulation of p62^dok induced by HFD or FFA enhances hepatic gluconeogenesis via inhibiting insulin signal transduction.     

Effect of glycine on body weight and lipid metabolism in mice

AIM: To study the effect of glycine on body weight and lipid metabolism in mice. METHODS: Mice were randomly divided into four groups, control, high-fat diet group (HF), glycine group (Gly), and glycine treatment group (Gly+HF). The mice were fed with normal diet and high-fat diet for 12 days, respectively, and then were treated with glycine solution by intraperitoneal injection. Finally, the serum was collected to measure serum lipid, epididymal fat-pads, pararenal fat-pads and abdominal fat-pads were taken out to weight. Moreover, pathologic changes in liver were observed. RESULTS: The body weight of HF group was obviously lower than that in control; the body weight and adipose tissue content of Gly group were obviously lower than those in control; the body weight and adipose tissue content of Gly+HF group were obviously lower than those in HF group; the levels of TC and TG in Gly group were obviously lower than those in control; there was no statistical difference in serum lipid between Gly+HF and HF groups. In addition, marked hepatic steatosis in HF group, and slight hepatic steatosis in Gly+HF group were found. CONCLUSION: Gly can decrease the body weight and adipose tissue content and serum lipid in normal diet and high-fat diet mice, and it also can prevent hepatic steatosis.     

Inhibitory effect of Wendan decoction on atherosclerotic plaque formation in ApoE-/- mice by regulating expression of membrane proteins involved in reverse cholesterol transport

AIM To explore the anti-atherosclerotic mechanism of Wendan decoction based on reverse cholesterol transport. METHODS Eight-week-old apolipoprotein E gene knockout （ApoE^-/-） mice with high-fat diet and daily drug gavage were randomly divided into model group, simvastatin group, and low-, middle- and high-dose Wendan decoction groups, with 15 mice in each group. The C57BL/6 mice of the same age served as control group. The mice were weighed once every week. After 10 weeks, the mice were anesthetized with chloral hydrate. The serum were collected for lipid level examination. The atherosclerotic plaque buildup in aortic root and whole aorta was observed by HE staining and oil red O staining, respectively. The levels of proteins related to cholesterol transport, ATP-binding cassette transporter A1 （ABCA1） and caveolin-1 in the aorta, and scavenger receptor class B type I （SR-BI） and CD36 in the liver, were quantified by Western blot. RESULTS Wendan decoction at middle dose inhibited the increase in the body weight of ApoE^-/- mice fed with high-fat diet （P<0.05）. Wendan decoction at different doses significantly reduced the serum levels of triglyceride, total cholesterol and low-density lipoprotein cholesterol in the ApoE^-/- mice （P<0.05 or P<0.01）, but had no effect on serum high-density lipoprotein cholesterol level （P>0.05）. Wendan decoction at different doses inhibited the formation of atherosclerotic plaques in whole aorta of the ApoE^-/- mice （P<0.05 or P<0.01）. Middle- and high-dose Wendan decoction significantly inhibited the formation of atherosclerotic plaques in the aortic root （P<0.05）. Bedsides, Wendan decoction at different doses increased the protein level of ABCA1 and decreased the protein level of caveolin-1 in the aorta of the ApoE^-/- mice （P<0.01）. Middle- and high-dose Wendan decoction increased the liver protein level of SR-BI in the ApoE^-/- mice （P<0.01）. However, Wendan decoction at different doses had no effect on the liver protein level of CD36 in the ApoE^-/- mice （P>0.05）. CONCLUSION Wendan decoction reduces the body weight, serum lipid levels and formation of atherosclerotic plaques in ApoE^-/- mice fed with high-fat diet, and its mechanism is related to up-regulation of ABCA1 protein level in the aorta and SR-BI protein level in the liver as well as down-regulation of caveolin-1 protein level in the aorta.     

Hyperlipidemia induces endothelial dysfunction in rats by increasing oxidative and nitrative stresses

AIM: To observe the effect of high-fat diet on the endothelial functions in rats. METHODS: Male SD rats (8 week old) were randomly divided into 2 groups to receive a regular or a high-fat diet, respectively. After 14 weeks, the animals were anesthetized and caval blood was collected to determine the lipid profile, fasting blood glucose and insulin levels. The aorta of the animals was isolated to observe the response of vasorelaxation to endothelium-dependent vasodilator acetylcholine (ACh) and endothelium-independent vasodilator SNAP(S-nitroso-N-acetyl penicillamine). In addition, the production of nitric oxide(NO) and superoxide, the expression of gp91^phox, and the activity of NO synthase(NOS) in the aortic tissues were measured. RESULTS: The lipid profile, the levels of fasting blood glucose and insulin were significantly increased in the plasma of rats fed with high-fat diet. A dose-dependent vasorelaxation to ACh was reduced, and the expression of gp91^phox, the production of superoxide and the activity of iNOS were enhanced in the aortic tissues of the rats fed with high-fat diet. CONCLUSION: High-fat diet induces endothelial dysfunction by increasing the oxidative and nitrative stresses.     

Effect of lipoic acid on redox regulation,digestive and absorptive function in intestine of mice fed high fat diet

AIM:To elucidate the molecular mechanisms of lipoic acid (LA) on redox regulation and digestive function in intestine of C57BL/6 mice fed high fat diet (HFD).METHODS:C57BL/6 mice were randomly assigned to one of three groups (n=8).The control group consumed an ordinary diet.The other two experimental groups were fed with a high fat diet, high fat plus 0.1% LA.After 6 weeks, the activities of digestive enzymes were examined.In order to evaluate the antioxidant status of the mice, superoxide dismutase (SOD), malondialdehyde (MDA), total antioxidant capacity (TAC) and reactive oxygen species (ROS) in intestinal homogenate were measured.To investigate the molecular mechanisms underlying the effects of LA, the gene expression profiles in intestine were examined using the GeneChip microarray system.RESULTS:A depressed antioxidant defense system, accompanied by digestive and absorptive function impairment, was observed in HFD-fed mice.These changes were partially restored in the LA-treated group.DNA microarray analysis of intestine showed that LA ingestion up-regulated the expression of genes related to free-radical scavenger enzymes, digestive enzymes and transporters.CONCLUSION:Treatment with LA improves redox homeostasis and the function of intestine in mice fed HFD.The mechanism may involve preventing oxidative stress by scavenging ROS directly and increasing those of free-radical scavenger enzymes gene expression indirectly.     

Effects of maternal high-fat diet on motor ability,learning and memory of male offspring mice in late adolescence

AIM To study the effects of maternal high-fat diet （HFD） on motor ability， learning and memory of male offspring mice in late adolescence and the underlying mechanism. METHODS The female rats were fed with HFD for 16 weeks until the end of lactation to establish the obesity model， and the offspring male rats were taken as the main research object. The motor coordination of offspring mice was studied by footprinting analysis and rotarod experiment， the change of motor ability of male offspring mice was studied by open field experiment， the change of learning memory behavior of offspring mice was studied by Morris water maze and new object recognition experiment， and the neurogenesis of dentate gyrus （DG） in hippocampus of offspring mice was observed by immunofluorescence staining. RESULTS The footprint angle of the offspring mice in maternal HFD group decreased significantly， and the stay time in rotarod of the offspring mice in maternal HFD group was significantly shorter than that of the offspring mice in maternal normal diet group（P<0.01）. In the open field experiment， the number of vertical times， the central time and the total distance of movement were significantly reduced， and the latency of water maze experiment and the preference index of new object recognition were significantly reduced. The results of immunofluorescence staining showed that the degree and complexity of neuron differentiation in DG area of hippocampus of offspring mice in maternal HFD group decreased significantly（P<0.01）. CONCLUSION Maternal HFD damages the movement and learning abilities of the male offspring in late adolescence by affecting the hippocampus neurogenesis.