Korean red ginseng (Panax ginseng) prevents obesity by inhibiting angiogenesis in high fat diet-induced obese C57BL/6J mice

Adipose tissue growth and development are thought to be associated with angiogenesis and extracellular matrix remodeling. Because ginseng has been shown to inhibit angiogenesis and matrix metalloproteinase (MMP) activity, we hypothesized that adipose tissue growth and obesity can be regulated by Korean ginseng (Panax ginseng C.A. Meyer). Wild-type C57BL/6J mice were fed for 8 weeks with a low fat diet, a high fat diet (HFD), or HFD supplemented with 0.5% or 5% Korean red ginseng extract. We measured body weight, adipose tissue mass, food intake, MMP activity, and the expression of genes involved in angiogenesis and MMPs. Administering ginseng to HFD-induced obese mice produced reductions in body weight and adipose tissue mass compared with untreated counterparts. Ginseng treatment decreased blood vessel density and MMP activity in adipose tissues. Ginseng also reduced mRNA levels of angiogenic factors (e.g., VEGF-A and FGF-2) and MMPs (e.g., MMP-2 and MMP-9), whereas it increased mRNA levels of angiogenic inhibitors (e.g., TSP-1, TIMP-1, and TIMP-2) in adipose tissues. These results demonstrate that ginseng effectively reduces adipose tissue mass and prevents obesity in diet-induced obese mice and that this process may be mediated in part through the anti-angiogenic actions of ginseng.     

The effect of obesity and tobacco smoke exposure on inflammatory mediators and matrix metalloproteinases in rat model

Obesity is characterized by hypertrophy of adipose tissue and chronic obstructive pulmonary disease (COPD) by lung damage; both diseases are associated with systemic low-grade inflammation. There are no animal models combining obesity and COPD; therefore, these diseases were induced simultaneously in rats to analyze their effects on the expression of inflammatory mediators and enzymes involved in lung tissue remodeling. Obesity was induced with sucrose (30%) for 4 months concomitant with tobacco smoke exposure (20 cigarettes/day, 5 days/wk) for the last 2 months. Were evaluated: body weight, abdominal fat, dyslipidemia, glucose tolerance test (GTT), histology, inflammatory mediators with qPCR and enzyme-linked immunosorbent assay, matrix metalloproteinases (MMP-2), MMP-9, MMP-12, TIMP-1 and TIMP-2 through qRT-PCR, and MMP-2 and MMP-9 by gelatin zymography. The rats on a sucrose diet exhibited increased body weight, abdominal fat, triglycerides, GTT, and plasma levels of insulin, adiponectin, leptin, resistin, IL-6, IL-1β, tumor necrosis factor-α (TNF-α) and IFN-γ, upregulated lung IL-6, IL-1β, TNF-α and IFN-γ, showing hyperplastic bronchial and alveolar epithelium. The animals exposed to sucrose and tobacco smoke exhibited decreased body weight, abdominal fat and plasma levels of leptin, resistin, IL-1β and IFN-γ, reducing inflammation but showing emphysematous lesions. Expression of gelatinases and MMP-12 augmented in the rats exposed to tobacco smoke alone or combined with sucrose. Zymography showed prominent gelatinases activity in all the experimental groups. These results suggest that simultaneous exposure to sucrose and tobacco smoke decreases inflammation but results in emphysematous lesions similar to those observed with tobacco smoke exposure, suggesting that obesity does not confer any protective effect against lung damage.     

Adipocyte-derived exosomal miR-27a induces insulin resistance in skeletal muscle through repression of PPARγ

OBJECTIVE To explore increasingly exosomal serum miR-27 a derived from adipocytes could be taken up by skeletal muscle tissue and induce insulin resistance in skeletal muscle in obese state. METHODS The association between miR-27 a and insulin resistance in skeletal muscle was determined in obese children,high-fat diet-induced miR-27 a knockdown obese mice,db/db mice and C2C12 cells overexpressing miR-27 a.The crosstalk mediated by exosomal miR-27 a between adipose tissue and skeletal muscle was determined in C2C12 cel s incubated with conditioned medium prepared from palmitate-treated 3 T3-L1 adipocytes. RESULTS After knockdown miR-27 a in obese insulin resistance mice,impaired insulin resistance, glucose intolerance and insulin resistance of skeletal muscle were partly restored. In high-fat diet group, the expressions of IRS-1 and GLUT4 in glucose uptake signal pathway of skeletal muscle were significantly decreased, while the expression of IRS-1 and GLUT4 was restored after miR-27 a knockdown. The content of FABP4, a marker specific for exosomes from adipocytes, was detected in sera, skeletal muscle, supernatant of adipocytes and co-cultured C2C12 cells; furthermore,exosomal miR-27 a in serum and adipocyte supernatants were detect, and fluorescence co-localization experiments were conducted to detect whether the exosomal miR-27 a in serum is mainly derived from adipocyte; finally,we used the supernatant of adipose tissue to construct conditioned media to treat with C2C12 cells, and detected whether adipocytes derived exosomal miR-27 a could impaired glucose uptake signaling pathway of skeletal muscle. the expressions of PPARγ silencing high-fat diet induced C57 BL/6 J obese mouse model and adenovirus intervention miR-27 a knockdown model were examined,and a C2C12 cell model overexpressing miR-27 a in the absence or presence with rosiglitazone(PPARγ activator)were established to test glucose consumption, glucose uptake, and glucose uptake signaling pathways of skeletal muscle cells. CONCLUSION These results identify a novel crosstalk signaling pathway between adipose tissue and skeletal muscle in the development of insulin resistance, and indicate that adipose tissue-derived miR-27 a may play a key role in the development of obesity-triggered insulin resistance in skeletal muscle.     

Antidiabetic and antiobesity effects of a highly selective β3-adrenoceptor agonist (CL 316,243)

A third β-adrenoceptor subtype has been cloned form the rat, mouse, and human genomes. The presence of these receptors primarily on adipose tissue has raised the possibility that β₃-adrenoceptor selective agonists may be useful antiobesity agents. CL 316,243 is a highly selective β₃-agonist; it has a <30,000 to 1 β₃-to-β₁-adrenoceptor selectivity ratio and a 10,000 to 1 β₃-to-β₂-adrenoceptor selectivity ratio in in vitro functional assays. In vivo, animals were treated with CL 314,698, a diester prodrug of CL 316,243, which is rapidly converted to CL 316,243. In obese (ob/ob) and diabetic (db/db) mice, treatment with CL 314,698 reduced their hyperglycemia to the euglycemia of their lean littermates, and decreased plasma insulin levels. In obese mice, the compound also caused decreased weight gain despite increased food consumption, and the decreased weight was due to loss of fat while lean body mass was spared. CL 314,698 treatment also improved both glucose and insulin tolerance in obese mice, suggesting that it decreased insulin resistance. CL 314,698 also prevented further weight gain, without affecting food consumption, in rats previously made obese by feeding a high fat diet. The compound reduced plasma insulin and triglyceride levels, and reduced fat pad weights, while having no effect on plasma glucose, cholesterol, thyroxine, or T₃ levels or on skeletal muscle weight. Decreased weight gain without decreased food consumption suggested that CL 316,243 stimulated thermogenesis. Treatment of obese mice for 3 weeks with CL 316,243 increased thermogenesis by 45% as measured by indirect calorimetry. Thus, CL 316,243 is a potent, β₃-adrenoceptor selective agonist with thermogenic, antidiabetic, and antiobesity properties in several models of non-insulin dependent diabetes and obesity.     

TIMP-1 is a key factor of fibrogenic response to bleomycin in mouse lung

Pulmonary fibrosis is characterized by the excessive deposition of extracellular matrix in the interstitium, resulting in respiratory failure. The role of remodeling mediators such as metalloproteinases (MMPs) and their inhibitors (TIMPs) in the fibrogenic process remains misunderstood. We investigated MMP-9, MMP-2, TIMP-1, TIMP-2 and TIMP-3 in the fibrotic response to bleomycin of fibrosis prone C57BL/6J and fibrosis resistant BALB/c mice. Mice were administered with 0.1 mg bleomycin by intranasal administration. Either 24 h or 14 days after, the mice were anesthetized and underwent either bronchoalveolear lavage (BAL) or lung removal. Collagen deposition in lung tissue was determined by hydroxyproline measurement, MMP activity was analyzed by zymography, and other mediators were analyzed by ELISA. TIMP-1 was localized in lung sections by immunohistochemistry and real time PCR was performed to gene expression in lung. Non parametric Mann-Whitney and Spearman tests were used for statistical analysis. Fourteen days after bleomycin administration, hydroxyproline assay and histological study revealed that BALB/c mice developed significantly less fibrosis compared to C57BL/6J mice. At day 1, bleomycin enhanced TIMP-1, MMP-2 and MMP-9 protein levels in BALF, and induced corresponding genes in lung tissue of both strains. The rise of Timp-1, Mmp-9 and Mmp-2 gene levels were significantly stronger in lungs of C57BL/6J, whereas gelatinase activities of MMP-2 and MMP-9 were similar. Immunohistochemistry revealed that TIMP-1 macrophages and epithelial cells were prominent TIMP-1 producers in both strains. At day 14, neither MMP-2 nor MMP-9 levels exhibited strain-dependent protein level or gene expression, although TIMP-1 was strongly associated with fibrosis. Interestingly, bleomycin induced neither Timp-2 nor Timp-3 in lung tissue at any time of the study. The present study shows that early altered regulation of TIMP-1 following bleomycin administration may be involved in bleomycin-induced pulmonary fibrosis.     

胰岛素增敏剂罗格列酮升高血液中镍纹样蛋白水平

目的 探讨胰岛素增敏剂罗格列酮对血液中镍纹样蛋白（METRNL）水平的影响。方法 高脂饮食3个月诱导胰岛素抵抗的肥胖小鼠,给予罗格列酮治疗1个月,葡萄糖耐量实验检测罗格列酮对小鼠糖耐量的作用,酶联免疫吸附实验检测血清中METRNL水平,实时定量PCR检测肌肉、肝脏、白色脂肪、棕色脂肪、脑、脾脏、肾脏等组织中METRNL的表达,以及棕色脂肪中线粒体蛋白的表达。结果 罗格列酮治疗改善了高脂饮食动物的糖耐量,同时血液中METRNL浓度也显著增高;罗格列酮治疗增加了棕色脂肪和肾脏组织中METRNL的表达,对肌肉、肝脏、白色脂肪、脑、脾脏的METRNL表达没有影响;罗格列酮治疗增加了棕色脂肪线粒体相关蛋白的表达。结论 胰岛素增敏剂罗格利酮可能通过提高棕色脂肪和肾组织的METRNL表达升高血清METRNL水平,提示METRNL可能参与了罗格列酮对糖尿病的治疗作用。     

Sustained improvement in glucose homeostasis in lean and obese mice following chronic administration of the beta 3 agonist SR 58611A

1. Acute SR 58611A (0.25 mg kg-1), was effective in reducing the blood glucose response to a glucose tolerance test (GTT) in normal lean (control) and spontaneously obese/diabetic CBA/Ca mice and to be equipotent to 1.25 mg kg-1 glibenclamide in lean mice. 2. Neither brown (BAT) nor white (WAT) adipose tissue lipogenesis was altered by acute SR 58611A (2 - 8 mg kg-1) in lean mice, but both increased significantly at the higher doses in the obese mice. 3. Acute SR 58611A produced a hypoglycaemia 40 min after dosing in lean and obese animals, the duration and potency of which was less than that of glibenclamide. Plasma insulin levels increased 20 min after acute SR 58611A and glibenclamide in lean and obese mice. 4. Chronic treatment (0.25 mg kg-1, 15 days) with SR 58611A increased its effectiveness in improving glucose tolerance, but did not affect the body weight (BW) or food intake of either lean or obese mice. 5. Acute and chronic SR 58611A prolonged the hypoglycaemic effect of exogenous insulin in lean but not obese mice. 6. In fed and fasted lean mice and in fasted obese mice chronic SR 58611A produced an acute hypoglycaemia 30 min post administration which was greater than after a single dose. 7. SR 58611A maintained its effectiveness in improving glucose tolerance in lean and obese mice over a dosing period of 15 days. The improvement in glucose tolerance was achieved at a dose less than that required to stimulate adipose tissue lipogenesis and which did not affect food intake or body weight.     

2型糖尿病大鼠肺组织基质金属蛋白酶－2、9及其抑制因子－1的表达变化

目的通过检测2型糖尿病大鼠肺组织中基质金属蛋白酶-2（MMP-2）、基质金属蛋白酶－9（MMP-9）及基质金属蛋白酶抑制因子－1（TIMP—1）的表达变化,探讨MMP－2、MMP－9及TIMP－1在糖尿病肺损伤中的作用。方法通过高糖、高脂饮食加腹腔注射小剂量链脲佐菌素（streptozotocin,STZ）的方法,建立2型糖尿病大鼠模型,采用光镜动态观察12周、24周时对照组、糖尿病组的大鼠肺组织的形态学改变,用MassoN三色染色观察肺组织胶原沉积情况,应用免疫组织化学方法检测2组大鼠肺组织MMP－2、MMP－9及TIMP－1的动态表达变化情况。结果糖尿病大鼠肺组织胶原含量明显增多,糖尿病大鼠肺组织MMP－2、MMP－9、TIMP－1表达增多,同时MMP－2／TIMP－1、MMP-9／TIMP－1比例也增加。随病情进展,上述变化更加明显。结论糖尿病大鼠出现了肺间质纤维化,MMP-2、9及TIMP－1表达增多及其比例紊乱参与了糖尿病肺组织病变的发生发展,可能是糖尿病肺纤维化发生的机制之一。     

Sarsasapogenin improves adipose tissue inflammation and ameliorates insulin resistance in high-fat diet-fed C57BL/6J mice

Insulin resistance is a major cause of type 2 diabetes and metabolic syndrome.Macrophage infiltration into obese adipose tissue promotes inflammatory responses that contribute to the pathogenesis of insulin resistance.Suppression of adipose tissue inflammatory responses is postulated to increase insulin sensitivity in obese patients and animals.Sarsasapogenin(ZGY)is one of the metabolites of timosaponin AIII in the gut,which has been shown to exert anti-inflammatory action.In this study,we investigated the effects of ZGY treatment on obesity-induced insulin resistance in mice.We showed that pretreatment with ZGY(80 mg·kg^?1·d^?1,ig,for 18 days)significantly inhibited acute adipose tissue inflammatory responses in LPS-treated mice.In high-fat diet(HFD)-fed obese mice,oral administration of ZGY(80 mg·kg^?1·d^?1,for 6 weeks)ameliorated insulin resistance and alleviated inflammation in adipose tissues by reducing the infiltration of macrophages.Furthermore,we demonstrated that ZGY not only directly inhibited inflammatory responses in macrophages and adipocytes,but also interrupts the crosstalk between macrophages and adipocytes in vitro,improving adipocyte insulin resistance.The insulin-sensitizing and anti-inflammatory effects of ZGY may result from inactivation of the IKK/NF-κB and JNK inflammatory signaling pathways in adipocytes.Collectively,our findings suggest that ZGY ameliorates insulin resistance and alleviates the adipose inflammatory state in HFD mice,suggesting that ZGY may be a potential agent for the treatment of insulin resistance and obesity-related metabolic diseases.     

Tissue-specific glucocorticoid reactivating enzyme, 11 beta-hydroxysteroid dehydrogenase type 1 (11 beta-HSD1)--a promising drug target for the treatment of metabolic syndrome

Obesity is closely associated with the Metabolic Syndrome, which includes insulin resistance, glucose intolerance, dyslipidemia and hypertension. The best predictor of these morbidities is not the total body fat mass but the quantity of visceral (e.g. omental, mesenteric) fat. Glucocorticoids play a pivotal role in regulating fat metabolism, function and distribution. Indeed, patients with Cushing-s syndrome (a rare disease characterized by systemic glucocorticoid excess originating from the adrenal or pituitary tumors) or receiving glucocorticoid therapy develop reversible visceral fat obesity. The role of glucocorticoids in prevalent forms of human obesity, however, has remained obscure, because circulating glucocorticoid concentrations are not elevated in the majority of obese subjects. Glucocorticoid action on target tissue depends not only on circulating levels but also on intracellular concentration. Locally enhanced action of gluccorticoids in adipose tissue and skeletal muscle has been demonstrated in the Metabolic Syndrome. Evidence has accumulated that enzyme activity of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1), which regenerates active glucocorticoids from inactive forms and plays a central role in regulating intracellular glucocorticoid concentration, is commonly elevated in fat depots from obese individuals. This suggests a role for local glucocorticoid reactivation in obesity and the Metabolic Syndrome. 11beta-HSD1 knockout mice resist visceral fat accumulation and insulin resistance even on a high-fat diet. Furthermore, fat-specific 11beta-HSD1 transgenic mice, those have increased enzyme activity to a similar extent seen in obese humans, develop visceral obesity with insulin and leptin resistance, dyslipidemia and hypertension. In adipocytes, both antidiabetic PPARgamma agonists and LXRalpha agonists significantly reduce 11beta-HSD1 mRNA and enzyme activity, suggesting that suppression of 11beta-HSD1 in adipose tissue may be one of the mechanisms by which these drugs exert beneficial metabolic effects. Recently reported selective inhibitors of 11beta-HSD1 can ameliorate severe hyperglycemia in the genetically diabetic obese mice. In summary, 11beta-HSD1 is a promising pharmaceutical target for the treatment of the Metabolic Syndrome.     

Insulin therapy stimulates lipid synthesis and improves endocrine functions of adipocytes in dietary obese C57BL/6 mice

Aim:

To evaluate whether insulin intervention could affect the metabolic and endocrine functions of adipose tissue.

Methods:

C57BL/6 mice were fed on a high-fat-diet for 12−16 weeks to induce insulin resistance. Insulin intervention was administered in the high-fat-diet mice for 4 weeks at 12 weeks (early insulin treatment) or 16 weeks (late insulin treatment). Intraperitoneal glucose tolerance tests were performed before and after insulin treatment. Expression levels of factors involved in the triglyceride synthesis and endocrine functions of adipose tissue including phosphoenolpyruvate carboxykinase (PEPCK-C), fatty acid synthase (FAS), aquaporin 7 (AQP7), adiponectin, visfatin, and interleukin-6 (IL-6) were determined by Western blot.

Results:

In the obese mice, glucose tolerance was impaired; triglyceride content was increased in the liver tissue; protein expression of FAS and adiponectin was decreased; expression of visfatin was increased in adipose tissue. After 4-week insulin treatment, glucose tolerance was improved; triglyceride content was decreased in the liver and skeletal muscle; expression of PEPCK-C, FAS, and adiponectin was increased in the adipose tissue; IL-6 and AQP7 expression was reduced in the fat. Early insulin treatment had better effect in increasing the expression of FAS and PEPCK-C and decreasing the expression of IL-6.

Conclusion:

These results indicate that insulin can target adipocytes for improvement of insulin sensitivity through stimulating triglyceride synthesis and partly improving endocrine functions.     

芹菜素改善肥胖型2型糖尿病小鼠胰岛素抵抗的实验研究

[目的]考察芹菜素对肥胖型2型糖尿病小鼠模型(db/db小鼠)精、脂代谢和胰岛素抵抗的影响.[方法]12只db/db小鼠分正常饮食对照组(6只),芹菜素组(6只,每天灌服200 mg/kg芹菜素),并以db/db小鼠的标准对照(C57BL/KsJ小鼠,6只)为正常对照,实验共8周,观察体重、血糖、血脂水平、胰岛素敏感性及葡萄糖负荷后胰岛素水平的变化,并取内脏脂肪行H＆E染色后进行组织学观察.[结果]芹菜素干预可显著防止db/db小鼠体重的增加,降低肥胖小鼠的空腹血糖水平,增加胰岛素敏感性,降低葡萄糖负荷后的胰岛素水平,与db/db对照组比较,差异有显著性(P＜0.05).[结论]芹菜素可防止肥胖型2型糖尿病小鼠的体重增加,改善糖、脂代谢及胰岛素抵抗.     

Sibutramine sensitivity assay revealed a unique phenotype of bombesin BB3 receptor-deficient mice

Sibutramine sensitivity assay in genetically obese (bombesin BB3 receptor (BRS-3)-deficient mice, KK-Ay mice, db/db mice and Zucker obese rat) and wild-type animals was examined. The sensitivity of Sibutramine (10 mg/kg, p.o.) in BRS-3-deficient mice was retained as well as normal animals; however, it was decreased in KK-Ay, db/db mice and Zucker obese rat. The suppression values of food intake in BRS-3-deficient, KK-Ay, db/db mice and Zucker obese rat were 49.8+/-5.8%, 16.1+/-4.7%, 0.1+/-2.8% and -2.0+/-2.2% (mean +/- S.E.), respectively. Next, we found that the contribution of hyperphagia was small in the progress of obesity in BRS-3-deficient mice by calculating energy efficiency. Our results indicate that there is an inverse relationship between the sensitivity to Sibutramine and the contribution of hyperphagia to the progress of obesity in animals.     

Comparison of vascular relaxation, lipolysis and glucose uptake by peroxisome proliferator-activated receptor-gamma activation in +db/+m and +db/+db mice

In this study, we determined the in vitro effect of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) activation on the aortic relaxation, lipolysis and insulin-induced [(3)H]-glucose uptake of the abdominal (omental) adipocytes of the non-diabetic (+db/+m) and obese/diabetic (+db/+db) mice. The expression of PPAR-gamma (mRNA and protein) in aorta and adipose tissues was evaluated and compared. Cumulative application of ciglitazone, pioglitazone and troglitazone (PPAR-gamma agonists) caused a concentration-dependent aortic relaxation (sensitive to 2-chloro-5-nitro-N-phenylbenzamide (GW9662) (1 microM, a selective PPAR-gamma antagonist) and N(omega)-nitro-l-arginine methyl ester (l-NAME) (20 microM, a nitric oxide synthase inhibitor)) with a maximum relaxation of approximately 30% (3 microM) in +db/+m mice, whereas no relaxation was observed in +db/+db mice. All PPAR-gamma agonists examined did not alter the basal lipolysis of both species, but forskolin caused a concentration-dependent lipolysis, with a greater magnitude observed in +db/+m mice. Insulin (0.1 and 1 microM) caused an enhancement of [(3)H]-glucose uptake into adipocytes with a greater magnitude in +db/+m mice. In contrast, none of the PPAR-gamma agonists tested (0.1, 1 and 10 microM) altered the basal and the insulin (0.1 microM)-induced [(3)H]-glucose uptake into adipocytes of both species. In addition, there was no difference in PPAR-gamma expression (mRNA and protein) in the aorta and adipose tissues between the species. In conclusion, our results demonstrate that PPAR-gamma is present in the abdominal (omental) adipose tissue and thoracic aorta. An acute activation of PPAR-gamma produced a small ( approximately 30%) aortic relaxation (nitric oxide/endothelium-dependent) of +db/+m mice. However, all PPAR-gamma agonists examined have no acute effect on lipolysis and the insulin-induced glucose uptake into adipocytes of both +db/+m and +db/+db mice.     

The anti-angiogenic herbal extracts Ob-X from Morus alba,Melissa officinalis,and Artemisia capillaris suppresses adipogenesis in 3T3-L1 adipocytes

Context: Growing adipose tissue is thought to require adipogenesis, angiogenesis, and extracellular matrix (ECM) remodeling. Close examination of developing adipose tissue microvasculature reveals that angiogenesis often precedes adipogenesis. Since our previous study demonstrated that Ob-X, the anti-angiogenic herbal composition composed of Melissa officinalis L. (Labiatae), Morus alba L. (Moraceae), and Artemisia capillaris Thunb. (Compositae), reduced adipose tissue mass in obese mice, we hypothesized that adipogenesis can be inhibited by Ob-X.

Objective: To investigate the effects of the anti-angiogenic herbal extracts Ob-X on adipogenesis in 3T3-L1 adipocytes.

Materials and methods: After differentiated 3T3-L1 adipocytes were treated with Ob-X, we studied the effects of Ob-X on triglyceride accumulation and expression of genes involved in adipogenesis, angiogenesis, and ECM remodeling.

Results: Treatment of cells with Ob-X inhibited lipid accumulation and adipocyte-specific gene expression caused by troglitazone or monocyte differentiation-inducing (MDI) mix. Ob-X reduced mRNA levels of angiogenic factors (vascular endothelial growth factor-A, -B, -C, -D, and fibroblast growth factor-2) and matrix metalloproteinases (MMPs; MMP-2 and MMP-9), whereas it increased mRNA levels of angiogenic inhibitors [(thrombospondin-1, tissue inhibitor of metalloproteinase-1 (TIMP-1), and TIMP-2)] in differentiated cells. MMP-2 and MMP-9 activities were also decreased in Ob-X-treated cells.

Discussion and conclusion: These results suggest that the anti-angiogenic herbal composition Ob-X inhibits differentiation of preadipocytes into adipocytes. These events may be mediated by changes in the expression of genes involved in lipogenesis, angiogenesis, and the MMP system. Thus, by reducing adipogenesis, anti-angiogenic Ob-X provides a possible therapeutic approach for the prevention and treatment of human obesity and its related disorders.     

Pandanus amaryllifoliusleaf extract improves insulin sensitivity in high-fat diet-induced obese mice

OBJECTIVE To investigate the effect of Pandanus amaryllifolius leaf in high-fat diet-induced insulin resistance in mice model.METHODS To induce obesity,male ICR mice were fed with a high-fat diet(45%fat)for six weeks.The mice were divided into four groups(n=8):non-obese control mice were treated with 5% gum arabic and obese mice were treated with Pandanus amaryllifolius(125and 250mg·kg-1·d-1),or 5% gum arabic.After six weeks of treatments,the fasting blood glucose,serum insulin,OGTT and fat cell protein expression of glucose transporter 4(GLUT4)were determined.RESULTS Administration of Pandanus amaryllifolius showed significantly(P<0.05)reduced the high blood glucose,inhibited the abnormal increase in blood glucose level during OGTT,and decreased the high level of serum insulin.Moreover,it is interesting that the protein expression of GLUT4 was effectively increased by Pandanus amaryllifolius.CONCLUSION These findings demonstrate that the extract from Pandanus amaryllifolius leaf possesses antihyperglycemic action in obese mice by improving insulin sensitivity and stimulating GLUT4 expression in adipose tissue.     

Involvement of adipokines in rimonabant‐mediated insulin sensitivity in ob/ob mice

Objectives It has been recently reported that blockade of type 1 cannabinoid (CB1) receptors by specific antagonists or genetic manipulation alleviates dyslipidaemia, hyperglycaemia and insulin resistance in animal models of obesity and type 2 diabetes. However, the precise role of adipokines in the insulin‐sensitising effects of the CB1 antagonist rimonabant is not clear. Methods ob/ob mice were treated with different doses of rimonabant and then subjected to an oral glucose tolerance test. The expression of different adipokines in white adipose tissue was analysed by quantitative real‐time PCR. Key findings Rimonabant (30 mg/kg) significantly inhibited body weight and fat pad weight gain (P < 0.05) and improved glucose tolerance. Gene expression analysis indicated that tumour necrosis factor‐α, visfatin and retinol binding protein‐4 were downregulated in the adipose tissue of ob/ob mice treated with rimonabant compared with controls, whereas adiponectin was significantly upregulated. Conclusions Rimonabant‐mediated alteration of adipokines in white adipose tissues may play a role in improving insulin sensitivity in obese animals.     

Regulation of microbiota–GLP1 axis by sennoside A in diet-induced obese mice

Sennoside A (SA) is a bioactive component of Chinese herbal medicines with an activity of irritant laxative, which is often used in the treatment of constipation and obesity. However, its activity remains unknown in the regulation of insulin sensitivity. In this study, the impact of SA on insulin sensitivity was tested in high fat diet (HFD)-induced obese mice through dietary supplementation. At a dosage of 30 mg/kg/day, SA improved insulin sensitivity in the mice after 8-week treatment as indicated by HOMA-IR (homeostatic model assessment for insulin resistance) and glucose tolerance test (GTT). SA restored plasma level of glucagon-like peptide 1 (GLP1) by 90% and mRNA expression of Glp1 by 80% in the large intestine of HFD mice. In the mechanism, SA restored the gut microbiota profile, short chain fatty acids (SCFAs), and mucosal structure in the colon. A mitochondrial stress was observed in the enterocytes of HFD mice with ATP elevation, structural damage, and complex dysfunction. The mitochondrial response was induced in enterocytes by the dietary fat as the same responses were induced by palmitic acid in the cell culture. The mitochondrial response was inhibited in HFD mice by SA treatment. These data suggest that SA may restore the function of microbiota–GLP1 axis to improve glucose metabolism in the obese mice.