This study aimed to examine the effect and underlying mechanism of Puerariae Lobatae Radix on insulin resistance in db/db mice with type 2 diabetes mellitus(T2DM) based on the analysis of intestinal flora. Fifty db/db mice were randomly divided into a model group(M group), a metformin group(YX group), a high-dose Puerariae Lobatae Radix group(YGG group), a medium-dose Puerariae Lobatae Radix group(YGZ group), and a low-dose Puerariae Lobatae Radix group(YGD group). Another 10 db/m mice were assigned to the normal group(K group). After continuous administration for eight weeks, body weight and blood sugar of mice were measured. Enzyme linked immunosorbent assay(ELISA) was used to detect glycosylated serum protein(GSP) and fasting serum insulin(FINS), and insulin resistance index(HOMA-IR) was calculated. The histopathological changes in the pancreas were observed by HE staining. Tumor necrosis factor(TNF)-α expression in the pancreas was detected using immunohistochemistry. The structural changes in fecal intestinal flora in the K, M, and YGZ groups were detected by 16S rRNA. Western blot was used to detect the expression of farnesoid X receptor(FXR) and takeda G protein-coupled receptor 5(TGR5) in the ileum, cholesterol 7α-hydroxylase(CYP7A1) and sterol 27α-hydroxylase(CYP27A1) in the liver, and G protein-coupled receptors 41(GPR41) and 43(GPR43) in the colon. Compared with the K group, the M group showed increased body weight, blood sugar, serum GSP, fasting blood glucose(FBG), and FINS, increased HOMA-IR, inflammatory infiltration of islet cells, necrosis and degeneration of massive acinar cells, unclear boundary between islet cells and acinar cells, disturbed intestinal flora, and down-regulated FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43. Compared with the M group, the YX, YGG, YGZ, and YGD groups showed decreased body weight, blood sugar, serum GSP, FBG, and FINS, islet cells with intact and clumpy morphology and clear boundary, necrosis of a few acinar cells, and more visible islet cells. The intestinal flora in the YGZ group changed from phylum to genus levels, and the relative abundance of intestinal flora affecting the metabolites of intestinal flora increased. The protein expression of FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43 increased. The results show that Puerariae Lobatae Radix can improve the inflammatory damage of pancreatic islet cells and reduce insulin resistance in db/db mice with T2DM. The mechanism of action may be related to the increase in the abundance of Actinobacteria, Bifidobacterium, and Bacteroides in the intestinal tract and the protein expression related to metabolites of intestinal flora.
Mice ; Animals ; Insulin Resistance ; Blood Glucose/metabolism* ; Diabetes Mellitus, Type 2/genetics* ; Pueraria/chemistry* ; Gastrointestinal Microbiome ; RNA, Ribosomal, 16S ; Body Weight ; Necrosis

Animals ; Cell Cycle Proteins/metabolism* ; Insulin Resistance/genetics* ; Liver/physiopathology* ; Mice ; Sirtuin 1/metabolism*

OBJECTIVE: To investigate the effect CD36 deficiency on muscle insulin signaling in mice fed a normal-fat diet and explore the possible mechanism. METHODS: Wild-type (WT) mice and systemic CD36 knockout (CD36^-/-) mice with normal feeding for 14 weeks (n=12) were subjected to insulin tolerance test (ITT) after intraperitoneal injection with insulin (1 U/kg). Real-time PCR was used to detect the mRNA expressions of insulin receptor (IR), insulin receptor substrate 1/2 (IRS1/2) and protein tyrosine phosphatase 1B (PTP1B), and Western blotting was performed to detect the protein expressions of AKT, IR, IRS1/2 and PTP1B in the muscle tissues of the mice. Tyrosine phosphorylation of IR and IRS1 and histone acetylation of PTP1B promoter in muscle tissues were detected using co-immunoprecipitation (Co-IP) and chromatin immunoprecipitation (ChIP), respectively. RESULTS: CD36^-/- mice showed significantly lowered insulin sensitivity with obviously decreased area under the insulin tolerance curve in comparison with the WT mice (P < 0.05). CD36^-/- mice also had significantly higher serum insulin concentration and HOMA-IR than WT mice (P < 0.05). Western blotting showed that the p-AKT/AKT ratio in the muscle tissues was significantly decreased in CD36^-/- mice as compared with the WT mice (P < 0.01). No significant differences were found in mRNA and protein levels of IR, IRS1 and IRS2 in the muscle tissues between WT and CD36^-/- mice (P>0.05). In the muscle tissue of CD36^-/- mice, tyrosine phosphorylation levels of IR and IRS1 were significantly decreased (P < 0.05), and the mRNA and protein levels of PTP1B (P < 0.05) and histone acetylation level of PTP1B promoters (P < 0.01) were significantly increased as compared with those in the WT mice. Intraperitoneal injection of claramine, a PTP1B inhibitor, effectively improved the impairment of insulin sensitivity in CD36^-/- mice. CONCLUSION CD36 is essential for maintaining muscle insulin sensitivity under physiological conditions, and CD36 gene deletion in mice causes impaired insulin sensitivity by up-regulating muscle PTP1B expression, which results in detyrosine phosphorylation of IR and IRS1.
Animals ; Gene Deletion ; Histones/genetics* ; Insulin ; Insulin Receptor Substrate Proteins/metabolism* ; Insulin Resistance/genetics* ; Membrane Cofactor Protein/genetics* ; Mice ; Mice, Knockout ; Muscles/metabolism* ; Phosphoric Monoester Hydrolases/metabolism* ; Protein Tyrosine Phosphatase, Non-Receptor Type 1/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; RNA, Messenger/metabolism* ; Receptor, Insulin/metabolism* ; Tyrosine/genetics* ; Up-Regulation

BACKGROUND: Prenatal stress can cause neurobiological and behavioral defects in offspring; environmental factors play a crucial role in regulating the development of brain and behavioral; this study was designed to test and verify whether an enriched environment can repair learning and memory impairment in offspring rats induced by prenatal stress and to explore its mechanism involving the expression of insulin-like growth factor-2 (IGF-2) and activity-regulated cytoskeletal-associated protein (Arc) in the hippocampus of the offspring. METHODS: Rats were selected to establish a chronic unpredictable mild stress (CUMS) model during pregnancy. Offspring were weaned on 21st day and housed under either standard or an enriched environment. The learning and memory ability were tested using Morris water maze and Y-maze. The expression of IGF-2 and Arc mRNA and protein were respectively measured by using RT-PCR and Western blotting. RESULTS: There was an elevation in the plasma corticosterone level of rat model of maternal chronic stress during pregnancy. Maternal stress's offspring exposed to an enriched environment could decrease their plasma corticosterone level and improve their weight. The offspring of maternal stress during pregnancy exhibited abnormalities in Morris water maze and Y-maze, which were improved in an enriched environment. The expression of IGF-2, Arc mRNA, and protein in offspring of maternal stress during pregnancy was boosted and some relationships existed between these parameters after being exposed enriched environment. CONCLUSIONS The learning and memory impairment in offspring of prenatal stress can be rectified by the enriched environment, the mechanism of which is related to the decreasing plasma corticosterone and increasing hippocampal IGF-2 and Arc of offspring rats following maternal chronic stress during pregnancy.
Animals ; Cytoskeletal Proteins/metabolism* ; Female ; Gene Expression Regulation ; Hippocampus/metabolism* ; Insulin-Like Growth Factor II/metabolism* ; Learning ; Learning Disabilities/psychology* ; Male ; Memory Disorders/psychology* ; Nerve Tissue Proteins/metabolism* ; Pregnancy ; Prenatal Exposure Delayed Effects/psychology* ; Random Allocation ; Rats ; Rats, Wistar ; Social Environment ; Stress, Psychological/genetics*

This study focused on the ameliorative effects of gypenosides(GPS) on insulin sensitivity and inflammatory factors in rats with type 2 diabetes mellitus(T2 DM) and explored their possible molecular mechanisms. After the successful establishment of T2 DM model, diabetic rats were randomly divided into four groups, including model group, GPS groups(200, 100 mg·kg~(-1)) and metformin group(100 mg·kg~(-1)), with healthy rats serving as the control. After 6-week intragastric administration, fasting blood glucose(FBG) and oral glucose tolerance were examined. The levels of insulin, C-peptide, tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), interleukin-6(IL-6) and C-reactive protein(CRP) in serum were examined. Then the homeostasis model assessment of insulin resistance(HOMA-IR) and insulin sensitivity index(ISI) were calculated. The protein expression levels of phosphorylated insulin receptor substrate-1(p-IRS-1) and phosphorylated protein kinase B(p-Akt) in skeletal muscle were measured by Western blot, as well as those of phosphorylated inhibitor of nuclear factor-κB(NF-κB) kinase β(p-IKKβ), phosphorylated alpha inhibitor of NF-κB(p-IκBα) and phosphorylated p65 subunit of NF-κB(p-p65) in adipose tissue. The relative expression levels of glucose transporter 4(GLUT4) mRNA in skeletal muscle and NF-κB mRNA in adipose tissue were measured by qRT-PCR, and the morphological changes of pancreatic tissue were observed. Compared with the model group, the GPS groups witnessed significant decrease in FBG, marked amelioration of impaired oral glucose tolerance and significant increase in ISI. Further, the high-dose GPS group saw significantly reduced HOMA-IR, TNF-α, IL-1β and CRP, significantly increased expression levels of p-IRS-1(Tyr), p-Akt and GLUT4, and markedly inhibited p-IRS-1(Ser), p-IKKβ, p-IκBα, p-p65 and NF-κB. The concentration of CRP and the expression levels of p-IRS-1(Ser), p-IKKβ, p-IκBα and NF-κB were remarkably reduced in the low-dose GPS group. However, GPS was found less effective in the regulation of serum insulin, C-peptide and IL-6 levels and the alleviation of pancreatic islet injury. The results indicated that GPS can reduce FBG and improve insulin sensitivity in diabetic rats possibly by regulating the NF-κB signaling pathway, inhibiting inflammation, and thereby regulating the expression of key proteins in the insulin signaling pathway.
Animals ; Diabetes Mellitus, Experimental/drug therapy* ; Diabetes Mellitus, Type 2/genetics* ; Gynostemma ; Insulin ; Insulin Resistance ; NF-kappa B/metabolism* ; Plant Extracts ; Rats ; Signal Transduction

To examine the effects of Populus tomentiglandulosa (PT) extract on the expressions of antioxidant enzymes and neurotrophic factors in the cornu ammonis 1 (CA1) region of the hippocampus at 5 min after inducing transient global cerebral ischemia (TGCI) in gerbils, TGCI was induced by occlusion of common carotid arteries for 5 min. Before ischemic surgery, 200 mg·kg PT extract was orally administrated once daily for 7 d. We performed neuronal nuclear antigen immunohistochemistry and Fluoro-Jade B staining. Furthermore, we determined in situ production of superoxide anion radical, expression levels of SOD1 and SOD2 as antioxidant enzymes and brain-derived neurotrophic factor (BDNF) and insulin-like growth factor I (IGF-I) as neurotrophic factors. Pretreatment with 200 mg·kg PT extract prevented neuronal death (loss). Furthermore, pretreatment with 200 mg·kg PT extract significantly inhibited the production of superoxide anion radical, increased expressions of SODs and maintained expressions of BDNF and IGF-I. Such increased expressions of SODs were maintained in the neurons after IRI. In summary, pretreated PT extract can significantly increase levels of SODs and protect the neurons against TGCI, suggesting that PT can be a useful natural agent to protect against TGCI.
Animals ; Brain-Derived Neurotrophic Factor ; genetics ; metabolism ; CA1 Region, Hippocampal ; drug effects ; metabolism ; Gerbillinae ; Humans ; Insulin-Like Growth Factor I ; genetics ; metabolism ; Male ; Neuroprotective Agents ; administration & dosage ; Plant Extracts ; administration & dosage ; Populus ; chemistry ; Pyramidal Cells ; drug effects ; metabolism ; Reperfusion Injury ; drug therapy ; genetics ; metabolism ; Superoxide Dismutase ; genetics ; metabolism ; Up-Regulation ; drug effects

This prospective study was designed to examine the combined influence of insulin resistance (IR) and inflammatory biomarker levels on type 2 diabetes mellitus (T2DM) among 1,903 Inner Mongolians. During follow-up, 205 (10.77%) participants developed T2DM, and the incidence of T2DM was higher among subjects with IR, elevated C-reactive protein (CRP), elevated sICAM-1, elevated sE-selectin, or the coexistences of IR with elevated CRP, elevated sICAM-1, elevated sE-selectin, and elevated angiotensin II (all P < 0.05) compared with patients without IR or any elevated biomarkers. In multivariate analysis, the odd ratios [OR, (95% confidence intervals)] for these conditions were 1.944 (1.405-2.691), 2.003 (1.449-2.767), 1.706 (1.232-2.362), 1.560 (1.123-2.165), 2.708 (1.809-4.054), 1.885 (1.155-3.078), 2.101 (1.340-3.295), and 2.260 (1.426-3.582), respectively. Our findings demonstrated that IR and elevated inflammatory biomarkers were associated with T2DM, and that the coexistence of IR and elevated inflammatory biomarkers increased the risk of T2DM.
Asian Continental Ancestry Group ; Biomarkers ; China ; epidemiology ; Cohort Studies ; Diabetes Mellitus, Type 2 ; blood ; epidemiology ; genetics ; Humans ; Inflammation ; metabolism ; Insulin Resistance ; genetics ; physiology ; Multivariate Analysis ; Odds Ratio ; Prospective Studies

BACKGROUNDTranscription factor 7-like 2 (TCF7L2)-rs7903146 polymorphism is associated with increased risk of type 2 diabetes. The response of insulin and insulin resistance to artichoke leaf extract (ALE) may be affected by TCF7L2-rs7903146 polymorphism.

OBJECTIVEThis study examined the effects of ALE supplementation on metabolic parameters of the TCF7L2-rs7903146 polymorphism in patients with metabolic syndrome (MetS).

DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONSThis double-blind clinical trial was conducted on 80 patients with MetS in Sina Clinic, Khoy, Iran. The patients were randomized into ALE or placebo groups to receive either ALE (1800 mg/d as four tablets) or matching placebo for 12 weeks.

MAIN OUTCOME MEASURESAnthropometric indices, blood pressure, glucose and lipid profile levels were measured before and after the study. Moreover, patients were genotyped for TCF7L2 polymorphism.

RESULTSALE supplementation decreased insulin level and the homeostasis model assessment of insulin resistance (HOMA-IR) in patients with the TT genotype of TCF7L2-rs7903146 polymorphism (P < 0.05). There was no significant interaction between blood pressure, glucose and lipid profile response to ALE supplementation.

CONCLUSIONThe responses of insulin and HOMA-IR to ALE supplementation have shown an interaction with single-nucleotide polymorphism rs7903146 in TCF7L2.

TRIAL REGISTRATIONIranian Registry of Clinical Trial IRCT201409033320N9.

Adult ; Blood Glucose ; metabolism ; Cynara scolymus ; Dietary Supplements ; Double-Blind Method ; Female ; Genotype ; Humans ; Insulin ; blood ; Insulin Resistance ; genetics ; Male ; Metabolic Syndrome ; blood ; drug therapy ; genetics ; Middle Aged ; Phytotherapy ; Plant Extracts ; pharmacology ; Polymorphism, Single Nucleotide ; Transcription Factor 7-Like 2 Protein ; genetics

Angiogenesis is a crucial process in the development of inflammatory diseases, including cancer, psoriasis and rheumatoid arthritis. Recently, several alkaloids from Picrasma quassioides had been screened for angiogenic activity in the zebrafish model, and the results indicated that 1-methoxycarbony-β-carboline (MCC) could effectively inhibit blood vessel formation. In this study, we further confirmed that MCC can inhibit, in a concentration-dependent manner, the viability, migration, invasion, and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro, as well as the regenerative vascular outgrowth of zebrafish caudal fin in vivo. In the zebrafish xenograft assay, MCC inhibited the growth of tumor masses and the metastatic transplanted DU145 tumor cells. The proteome profile array of the MCC-treated HUVECs showed that MCC could down-regulate several angiogenesis-related self-secreted proteins, including ANG, EGF, bFGF, GRO, IGF-1, PLG and MMP-1. In addition, the expression of two key membrane receptor proteins in angiogenesis, TIE-2 and uPAR, were also down-regulated after MCC treatment. Taken together, these results shed light on the potential therapeutic application of MCC as a potent natural angiogenesis inhibitor via multiple molecular targets.
Angiogenesis Inhibitors ; chemistry ; pharmacology ; Animals ; Carbolines ; chemistry ; pharmacology ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Epidermal Growth Factor ; genetics ; metabolism ; Fibroblast Growth Factors ; genetics ; metabolism ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; metabolism ; Humans ; Insulin-Like Growth Factor I ; genetics ; metabolism ; Neovascularization, Physiologic ; drug effects ; Picrasma ; chemistry ; Plant Extracts ; chemistry ; pharmacology ; Receptor, TIE-2 ; genetics ; metabolism ; Zebrafish ; embryology

Catalpol, a major bioactive component from Rehmannia glutinosa, which has been used to treat diabetes. The present study was designed to elucidate the anti-diabetic effect and mechanism of action for catalpol in db/db mice. The db/db mice were randomly divided into six groups (10/group) according to their blood glucose levels: db/db control, metformin (positive control), and four dose levels of catalpol treatment (25, 50, 100, and 200 mg·kg), and 10 db/m mice were used as the normal control. All the groups were administered orally for 8 weeks. The levels of fasting blood glucose (FBG), random blood glucose (RBG), glucose tolerance, insulin tolerance, and glycated serum protein (GSP) and the globe gene expression in liver tissues were analyzed. Our results showed that catalpol treatment obviously reduced water intake and food intake in a dose-dependent manner. Catalpol treatment also remarkably reduce fasting blood glucose (FBG) and random blood glucose (RBG) in a dose-dependent manner. The RBG-lowering effect of catalpol was better than that of metformin. Furthermore, catalpol significantly improved glucose tolerance and insulin tolerance via increasing insulin sensitivity. Catalpol treatment significantly decreased GSP level. The comparisons of gene expression in liver tissues among normal control mice, db/db mice and catalpol treated mice (200 and 100 mg·kg) indicated that there were significant increases in the expressions of 287 genes, whichwere mainly involved in lipid metabolism, response to stress, energy metabolism, and cellular processes, and significant decreases in the expressions of 520 genes, which were mainly involved in cell growth, death, immune system, and response to stress. Four genes expressed differentially were linked to glucose metabolism or insulin signaling pathways, including Irs1 (insulin receptor substrate 1), Idh2 (isocitrate dehydrogenase 2 (NADP), mitochondrial), G6pd2 (glucose-6-phosphate dehydrogenase 2), and SOCS3 (suppressor of cytokine signaling 3). In conclusion, catalpol ecerted significant hypoglycemic effect and remarkable therapeutic effect in db/db mice via modulating various gene expressions.
Animals ; Blood Glucose ; metabolism ; Diabetes Mellitus, Experimental ; drug therapy ; genetics ; metabolism ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; administration & dosage ; analysis ; Gene Expression ; drug effects ; Glucosephosphate Dehydrogenase ; genetics ; metabolism ; Humans ; Hypoglycemic Agents ; administration & dosage ; Insulin ; metabolism ; Insulin Receptor Substrate Proteins ; genetics ; metabolism ; Iridoid Glucosides ; administration & dosage ; analysis ; Isocitrate Dehydrogenase ; genetics ; metabolism ; Liver ; drug effects ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Rehmannia ; chemistry ; Suppressor of Cytokine Signaling 3 Protein ; genetics ; metabolism