Effect of Rubus irritans Focke extract on differentiation of 3T3-L1 preadipocytes / 中国药理学通报

Aim To study the effect of Rubus irritans Focke extract on adipogenic differentiation of 3T3-L1 preadipocytes, and to further explore the potential mechanism of Rubus irritans Focke on adipocyte metabolism, so as to provide a new basis for the prevention and treatment of obesity. Methods Rubus irritans Focke extract was separated and prepared by MCI medium pressure chromatographic column. MTT method was used to detect cell proliferation, and oil red 0 staining and kit test was used to to detect the level of lipid accumulation. Western blot was employed to detect the expressions of peroxisome proliferator-activated receptor ¦y (PPAR7), CCAAT enhancer binding protein a (C/ EBPa), adenosine 5'-monophosphate activated protein kinase (AMPK) and phosphorylated AMPK (p-AMPK) protein. Results When the concentration of Rubus irritans Focke extract was less than 100 mg •L

Effect of Daizongfang on Insulin Resistance of 3T3-L1 Adipocytes Induced by Different Methods / 中国实验方剂学杂志

Objective:To investigate the effects of Daizongfang （DZF） on insulin resistance （IR） of adipocytes induced by different methods. Method:The cocktail induction method was adopted to induce the differentiation and maturity of 3T3-L1 preadipocytes. An IR model in mature adipocytes was established by the induction of palmitic acid （PA）， high-concentration glucose （HG）， and dexamethasone （DEX）. DZF extracts at different concentrations （2.0， 0.5， 0.1 g·L^-1） intervened for 24 hours. A model group， a rosiglitazone （RSG） group， and a blank control group were set up at the same time. The glucose concentration in the culture supernatant was measured by the glucose oxidase-peroxidase （GOD-POD） method. Glucose consumptions under basic conditions （G_Basic） and insulin stimulation （G_Ins） were calculated to evaluate the insulin sensitivity index （ISI）. The mRNA expression of glucose transporter 4 （GLUT4） was detected by the real-time polymerase chain reaction （PCR）. Result:Compared with the model group， the DZF （2.0 g·L^-1） showed increased G_Basic， G_Ins， and ISI in three IR models （<italic>P</italic><0.05， <italic>P</italic><0.01）. In addition， for the PA-induced IR model， G_Basic and G_Ins in the DZF （0.5 g·L^-1） group were elevated （<italic>P</italic><0.01）， and G_Basic， G_Ins， and ISI in the RSG group increased （<italic>P</italic><0.05， <italic>P</italic><0.01）. For the HG-induced IR model， G_Ins and ISI increased in the DZF （0.5 g·L^-1） group （<italic>P</italic><0.05）， and G_Basic， G_Ins， and ISI were elevated in the RSG group （<italic>P</italic><0.01）. For the DEX-induced IR model， G_Ins and ISI increased in the RSG group （<italic>P</italic><0.01）. In the three models， there were differences among groups with different doses. G_Basic， G_Ins， and ISI in the high-dose DZF group increased in varying degrees compared with those in the medium- and low-dose DZF groups （<italic>P</italic><0.05）. In the three models， the DZF （2.0 g·L^-1） group and the RSG group both increased GLUT4 mRNA expression （<italic>P</italic><0.05）. Conclusion:DZF can reduce IR of adipocytes induced by HG， DEX， or PA in a dose-dependent manner and increase glucose uptake in an insulin-independent manner， which may be related to the increase in GLUT4 expression.

Effect of protease inhibitor from Agaricus bisporus on glucose uptake and oxidative stress in 3T3-L1 adipocytes

Objective: To explore the effect of the protease inhibitor from Agaricus bisporus (J.E. Lange) Imbach (AbPI) on glucose uptake and oxidative stress in 3T3-L1 adipocytes. Methods: Adipocytes were differentiated and stained with Oil-Red-O staining to confirm adipogenesis. The toxic/protective effect of AbPI on the adipocytes was determined by MTT assay, intracellular reactive oxygen species generation through flow cytometry, and morphologically through confocal microscopy using propidium iodide, 4,6-diamino-2-phenylindol dihydrochloride, and 2',7'-dichlorofluorescein diacetate dyes. The uptake of fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose by adipocytes was also studied through confocal microscopy. Results: MTT assay showed that the cell survival rate was (28.00±3.00)%, (92.33±2.60)%, and (71.34±2.10)% in the presence of 2 mM H

Caulerpa okamurae extract attenuates inflammatory interaction, regulates glucose metabolism and increases insulin sensitivity in 3T3-L1 adipocytes and RAW 264.7 macrophages / 中西医结合学报

OBJECTIVE@#To examine whether Caulerpa okamurae ethanolic extract (COE) could inhibit obesity-mediated inflammation, improve glucose metabolism and increase insulin sensitivity, using in vitro cell models of RAW 264.7 macrophages and 3T3-L1 adipocytes.@*METHODS@#We cocultured 3T3-L1 adipocytes in direct contact with lipopolysaccharide-stimulated RAW 264.7 macrophages and induced insulin resistance in 3T3-L1 adipocytes with tumor necrosis factor-α (TNF-α) in the presence or absence of 250 µg/mL of COE. We investigated various markers of inflammation, glucose regulation and insulin sensitivity in these models using Griess reagent to measure nitric oxide (NO) production, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxyglucose to measure glucose uptake, Western blot analysis to quantify protein expression and reverse transcriptase-polymerase chain reaction to evaluate mRNA expression.@*RESULTS@#We found that COE (250 µg/mL) significantly inhibited the lipopolysaccharide-induced inflammatory response in RAW 264.7 macrophages by downregulating NO production, nitric oxide synthase 2 expression and nuclear translocation of nuclear factor-κB. COE also showed similar anti-inflammatory activity in coculture, along with decreased TNF-α, interleukin-6 and monocyte chemoattractant protein mRNA expression. In addition, COE also improved glucose uptake in coculture by upregulating glucose transporter-4 (GLUT-4) and adiponectin and reducing serine phosphorylation of insulin receptor substrate-1 (IRS1). In the TNF-α-induced insulin resistance model of 3T3-L1 adipocytes, COE significantly improved both basal and insulin-stimulated glucose uptake, accompanied by phosphorylation of IRS1 at tyrosine 632, phospho-5' adenosine monophosphate-activated protein kinase α and glycogen synthase kinase-3β (Ser9) as well as upregulation of GLUT-4.@*CONCLUSION@#Together, these findings suggest that COE has potential to treat or prevent obesity-induced metabolic disorders.

Effect of protease inhibitor from Agaricus bisporus on glucose uptake and oxidative stress in 3T3-L1 adipocytes

Objective: To explore the effect of the protease inhibitor from Agaricus bisporus (J.E. Lange) Imbach (AbPI) on glucose uptake and oxidative stress in 3T3-L1 adipocytes. Methods: Adipocytes were differentiated and stained with Oil-Red-O staining to confirm adipogenesis. The toxic/protective effect of AbPI on the adipocytes was determined by MTT assay, intracellular reactive oxygen species generation through flow cytometry, and morphologically through confocal microscopy using propidium iodide, 4,6-diamino-2-phenylindol dihydrochloride, and 2',7'-dichlorofluorescein diacetate dyes. The uptake of fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose by adipocytes was also studied through confocal microscopy. Results: MTT assay showed that the cell survival rate was (28.00±3.00)％, (92.33±2.60)％, and (71.34±2.10)％ in the presence of 2 mM H2O2, AbPI alone, and AbPI and H2O2 both, respectively, in comparison to the control. Oil-Red-O staining indicated that AbPI enhanced adipogenesis. AbPI stimulated the glucose uptake by adipocytes similar to the drug rosiglitazone, and showed insulin-sensitizing effect in the presence of insulin, but failed to stimulate the uptake in the absence of insulin. Intracellular reactive oxygen species generation was reduced in differentiating adipocytes upon AbPI treatment. Confocal microscopy showed that the damaged cell population rose to 3.50％, 117.84％, and 261.50％ in the presence of AbPI alone, AbPI with H2O2, and H2O2 alone, respectively. Conclusions: The protease inhibitor enhances glucose uptake by adipocytes and exhibits a cytoprotective effect on them.

Flavonoids kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone inhibit mitotic clonal expansion and induce apoptosis during the early phase of adipogenesis in 3T3-L1 cells / 中西医结合学报

OBJECTIVE@#Kaempferide and 4,2'-dihydroxy-4',5',6'-trimethoxychalcone (DTMC) are two major flavonoids found in Chromolaena odorata Linn. leaf extract. The aim of this study was to elucidate the mechanism by which these two flavonoids exerted their effect on adipogenesis. The inhibitory effect of kaempferide and DTMC on adipocyte differentiation and their mechanisms involving mitotic clonal expansion (MCE) and apoptosis during the early stage of adipogenesis were investigated.@*METHODS@#Confluent 3T3-L1 preadipocytes were induced to differentiate and exposed to the flavonoids during various phases of differentiation. Intracellular lipid accumulation, cell density and expression of the transcription factors peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding proteins α were assessed using AdipoRed, Oil red O and Western blot assays. Effects of both flavonoids on cell proliferation and apoptosis were also determined by carboxyfluorescein diacetate succinimidyl ester and annexin V-fluorescein isothiocyanate/propidium iodide-staining assays, respectively.@*RESULTS@#Kaempferide and DTMC showed significant, concentration-dependent anti-adipogenic activity and effect on cell density in the early phase of adipogenesis. The expression of the transcription factors seemed to be reduced when the treatment was prolonged or in the early phase of adipogenesis. These flavonoids interrupted MCE via inhibition of preadipocyte proliferation and induction of apoptosis. DTMC was nearly three times more potent than kaempferide in inducing apoptosis.@*CONCLUSION@#Kaempferide and DTMC exerted their anti-adipogenic activity through inhibition of MCE, either by suppressing cell proliferation or by inducing apoptosis during the early phase of differentiation.

Jatrorrhizine regulates GLUTs with multiple manners for hypoglycemic effect in insulin-resistance 3T3-L1 adipocytes / 中国中药杂志

This paper aimed to investigate the hypoglycemic effect and relative mechanism of jatrorrhizine in insulin-resistance (IR)-3T3-L1 adipocytes. The 3T3-L1 preadipocytes were used to induce mature adipocytes, then the stable IR model was established with 1 μmol·L⁻¹ dexamethasone. The adipocytes were divided into normal group, IR model group, rosiglitazone positive group and jatrorrhizine group (0.5, 1, 5, 10, 20 μmol·L⁻¹). After different time points (12, 24, 30, 36, 48 h) treatment, glucose content of 3T3-L1 adipocytes was detected by the glucose oxidase peroxidase method and TG content was measured by glycerol phosphate oxidase method, whereas cell viability was detected by CCK-8 assay. Furthermore, the protein expression levels of insulin receptor substrate 2 (IRS2), phosphinositide-3-kinase regulatory subunit 1(PI3KR1), phosphorylated protein B [p-AKT (Ser473)], phosph-AMP-activated protein [p-AMPK (Thr172)], and glucose transporter type 4/1/2 (GLUT4/1/2) were detected by Western blot assay. The results showed that as compared with the normal group, the glucose consumptionwas significantly decreased in IR model group(<0.01); whereas 0.5, 1, 5, 10, 20 μmol·L⁻¹ jatrorrhizine and rosiglitazone group elevated IR-3T3-L1 cells glucose consumption (<0.01) at 36 h and 48 h administration as compared with IR group. The optimal administration time was 48 h for jatrorrhizine. 1, 5, 10, 20 μmol·L⁻¹ of jatrorrhizine decreased the TG content in 3T3-L1 adipocytes for 48 h administration (<0.05). The protein expression levels of IRS2, PI3KR1, p-AKT (Ser473), p-AMPK (Thr172), GLUT4/1/2 were significantly up-regulated by different concentrations of jatrorrhizine and rosiglitazone (<0.01). The results showed that jatrorrhizine increased glucose uptake with elevated glucose consumption, whereas reduced intracellular TG content in IR-3T3-L1 adipocytes. Moreover, it intervened classic insulin signal pathway IRS2/PI3KR1/p-AKT/GLUT4 and increase AMPK protein phosphorylation level for the activation of GLUT1/4 for insulin sensibility. Thus, jatrorrhizine could effectively regulate the GLUTs with multiple manners for hypoglycemic effect.

Exendin-4 improves insulin resistance by declining expression of endoplasmic reticulum stress markers in 3T3-L1 adipocytes / 中国病理生理杂志

AIM: To explore the effects of exendin-4 (EX-4) on endoplasmic reticulum stress (ERS)-mediated insulin resistance in the 3T3-L1 adipocytes.METHODS: In vitro 3T3-L1 pre-adipocytes were differentiated into adipocytes, and the cells were treated with tunicamycin (TM), tauroursodeoxycholic acid (TUDCA) or EX-4, respectively.The cell viability was measured by MTT assay.The glucose consumption was determined by glucose oxidase assay to evaluate insulin sensitivity of the 3T3-L1 adipocytes with different interventions.The protein levels of p-Akt, Akt and endoplasmic reticulum stress markers, including inositol requiring enzyme-1 (IRE1), p-IRE1, JNK, p-JNK, protein kinase R-like endoplasmic reticulum kinase (PERK), p-PERK, eukaryotic initation factor 2 alpha (eIF2a), p-eIF2a, activating transcription factor-6(ATF-6) were detected by Western blot.RESULTS: The insulin-stimulated glucose consumption and the protein level of p-Akt were inhibited by TM at 5 mg/L for 5 h (P<0.05), while they were increased when the cells were treated with TUDCA at 1 mmol/L or EX-4 at 100 nmol/L for 24 h (P<0.05).The effects above induced by TM (5 mg/L for 5 h) were also blunted by pretreating with TUDCA at 1 mmol/L or EX-4 at 100 nmol/L for 24 h (P<0.05).The protein levels of ERS markers such as p-IRE1, p-JNK, p-PERK, p-eIF2a and ATF-6 were significantly increased by treating with TM at 5 mg/L for 5 h, whereas 24 h pre-treatment with TUDCA or Ex-4 alleviated the ERS of the 3T3-L1 adipocytes induced by TM.The expression of total IRE1, JNK, PERK and eIF2a was not changed in different groups.CONCLUSION: Exendin-4 improves endoplasmic reticulum stress mediated insulin resistance in 3T3-L1 adipocytes.

Highuric acid induced insulin resistance in 3T3-L1 adipocyte and its mechanism / 中国糖尿病杂志

Objective To investigate the effect of high uric acid(HUA) on insulin sensitivity (IS) in 3T3-L1 adipocytes and its mechanism. Methods 3T3-L1 adipocytes were pretreated with HUA with or without NAC,and then stimulated by insulin. The cell viability of 3T3-L1 adipocytes was detected by CCK-8 assay. The glucose consumption was measured by glucose oxidase method. The levels of phospho-IRS-1,phospho-Akt and GluT4 protein were tested by western blot. Results HUA could inhibit insulin-induced glucose consumption,phosphorylation of Akt (Thr308),dephosphorylation of IRS-1 (Ser307) and the GluT4 protein expression (P<0.05). All the above could be blocked by NAC(P<0.05). Conclusion HUA can inhibit inulin stimulated IRS-1/Akt signaling and GluT4 expression,and thus induced insulin resistance in 3T3-L1 adipocytes.

Effects of orientin on insulin resistance in 3T3-L1 adipocytes and its mechanism / 中国药理学通报

Aim To investigate the effect of orientin on proliferation and differentiation of 3T3-L1 pre-adipocytes and on insulin resistance(IR) in 3T3-L1 adipocytes and the possible mechanisms.Methods MTT assay and oil red O staining were applied to investigate the proliferation and the differentiation of 3T3-L1 pre-adipocytes, respectively.The intracellular triglyceride(TG) contents were detected by enzymatic analysis.IR model was induced with dexamethasone.A fluorescent glucose analogue, 2-NBDG, was used to measure the rate of glucose uptake.Western blot was used to detect the protein level of GLUT4 and phosphorylation of AMPK and ACC.The GLUT4 translocation was measured by fluorescent-immunohistochemistry.Results Orientin decreased the formation of lipid droplets and intracellular TG contents(P<0.01) in a concentration-dependent manner(P<0.05), but it had no obvious effects on the cell vitality.Under the IR state, orientin significantly increased 3T3-L1 adipocytes glucose uptake(P<0.05).Meanwhile, orientin up-regulated the protein expression of p-AMPK, p-ACC, and enhanced GLUT4 translocation and its expression.Conclusion Orientin can effectively inhibit the differentiation of 3T3-L1 pre-adipocytes and increase insulin sensitivity due to the activation of AMPK/GLUT4 signal pathway.

Gegen Qinlian decoction activates PPARγ to ameliorate adipocytic insulin resistance in diabetic SD rats and IR-3T3-L1 adipocytes / 中国中药杂志

To investigate the effects of Gegen Qinlian decoction(GQD) in improving adipocytic insulin resistance(IR) and explore its related molecular mechanism. Diabetic rats models were induced by high glucose and high-fat diet with a small dose of streptozotocin, and after GQD treatment for 3 months, blood biochemical indexes such as fasting blood-glucose(FBG), insulin, glycosylated serum protein(GSP) and HOMA-IRI were detected and assessed. After the total RNA was extracted from the adipose tissue of diabetic SD rats, PPARγ, ADPN, GLUT4, GLUT2, ACACA and ACACB mRNA expression levels were separately detected by qPCR. Then, stable IR-3T3-L1 adipocyte model was built with 1 μmol•L⁻¹ dexamethasone. After the cell viability was detected by CCK-8 assay, 5%, 10% and 15% GQD-containing serum(GQD-CS) were respectively used to treat IR-3T-L1 adipocytes for 24 h. The contents of glucose, nonesterified fatty acid(NEFA) and adiponectin in cell culture supernatants were separately detected whereas the intracellular triglyceride(TG) contents of IR-3T3-L1 adipocytes were also measured. The ADPN, PPARγ and GLUT4 mRNA and protein expression levels were respectively detected by qPCR and Western blot in IR-3T3-L1 adipocytes. Results showed that GQD significantly decreased fasting blood glucose, insulin and GSP(P<0.01), and down-regulated HOMA-IRI(P<0.05) after the high-fat diet/streptozotocin-induced diabetic SD rats were treated for three months, with a good hypoglycemic effect. Moreover, PPARγ, ADPN, GLUT4, GLUT2, ACACA and ACACB mRNA expression levels were significantly elevated in the adipose tissue of GQD-treated diabetic SD rats. The 5%, 10% and 15% GQD-CS significantly increased glucose consumption of IR-3T3-L1 adipocytes at 24 h treatment(P<0.01), significantly decreased the intracellular TG content (P<0.01), and down-regulated NEFA to a certain extent but not significantly. Moreover, GQD-CS significantly up-regulated GLUT4 and ADPN expression. The results indicated that GQD could activate PPARγ to ameliorate adipocytic insulin resistance in the diabetic SD rats and IR-3T3-L1 adipocytes.

The Inhibitory Effect of Testosterone on PPARγ-induced Adipogenesis

BACKGROUND: Peroxisome proliferator-activated receptor γ (PPARγ) plays a major role in adipocyte differentiation. Testosterone is well known for inhibiting adipocyte metabolism in men. To investigate the inhibitory mechanism of testosterone on adipogenesis, this study evaluated the effects of testosterone on PPARγ expression and activity in adipocytes using in vitro approaches. METHODS: After differentiated 3T3-L1 adipocytes were treated with PPARγ agonist troglitazone and sex hormone testosterone, the effects of testosterone on troglitazone-induced triglyceride accumulation and expression of genes involved in adipogenesis were investigated. We also investigated whether testosterone regulates troglitazone-induced PPARγreporter activity in 3T3-L1 preadipocytes. RESULTS: Testosterone decreased triglyceride accumulation in differentiated 3T3-L1 cells compared with the vehicle treated control group. Testosterone also decreased the expression of PPARγ mRNA as well as PPARγ dependent adipocyte-specific genes, such as adipocyte fatty acid binding protein and tumor necrosis factor α. Moreover, testosterone treatment inhibited triglyceride accumulation, and the expression of PPARγ and adipocyte-specific genes caused by troglitazone in differentiated 3T3-L1 cells. Testosterone decreased troglitazone-induced PPARγ reporter activity. Also, treatment with testosterone led to an inhibition of troglitazone-induced PPARγ reporter activity in PPARγ and androgen receptor (AR) expressed 3T3-L1 preadipocytes. CONCLUSION: These results suggest that testosterone interferes with the actions of PPARγ on adipogensis by an AR-dependent component. In addition, this study may have provided valuable molecular and biological insights regarding testosterone therapy in obese hypogonadal men.

Kudzu root (Ge-Gen) regulates on glucose and lipid metabolism to ameliorating insulin resistance on 3T3-L1 adipocytes / 中国中药杂志

This study aimed to explore the mechanism of Chinese traditional medicine, Kudzu root(Chinese name：Ge-Gen; Latin name： Puerariae Lobatae Radix) how to improving insulin resistance (IR) through the regulation of the glucose and lipid metabolism in the IR-3T3-L1 adipocytes. After the 3T3-L1 mouse preadipocytes were differentiated into mature adipocytes, IR model(IR-3T3-L1) was built with 1 μmol•L-1 dexamethasone treatment for 96 h. IR adipocytes were treated with different concentrations (5%,10% and 15%) of Ge-Gen containing serum (GG-CS)for 12 h or 24 h, whereas rosiglitazone group as positive control in this study. The glucose contents in cell culture supernatants were detected by glucose oxidase assay and the intracellular triglyceride (TG) contents were measured by glycerol phosphate oxidase assay respectively.The mRNA expression levels of PPARγ, ADPN, GLUT4, LPL, FABP4 and FASn gene were determined by real-time quantitative PCR(qPCR).Results showed that IR-3T3-L1 adipocytes significantly increased glucose consumption (P<0.01)and decreased TG contents (P<0.01) as compared with the normal control group, the glucose consumption significantly increased with the treatment of GG-CS (P<0.01) by dose-dependent and time-dependent manners,whereas the intracellular TG content was sigificantly decreased (P<0.01) by dose-dependent manner.qPCR analysis revealed that 10% and 15% GG-CS significantly up-regulated the mRNA expression level of PPARγ, ADPN and GLUT4 (P<0.01) with the same dose-dependent manner,whereas the GLUT4 mRNA expression was showed similar expression pattern with the treatment of 10% and 15% GG-CS (P<0.01).We also detected the mRNA expression levels of several important lipid-metabolizing enzymes such as LPL, FASn and FABP4 by PPARγ regulation. 15% GG-CS elevated LPL mRNA expression (P<0.05);10% and 15% GG-CS enhanced the FASn mRNA expression (P<0.01), whereas 5%,10% and 15% GG-CS down-regulated FABP4 mRNA expression (P<0.01). Together, our results indicated that GG could regulate the glucose and lipid metabolism to ameliorate IR with multi-target manners in 3T3-L1 adipocytes.

Effect of Sanhuang Decoction on glucose and lipid metabolism in 3 T3-L1 adipocytes / 中国药理学通报

Aim ToobservetheeffectofSanHuang Decoction (SHD )on glucose and lipid metabolism in insulin resistance(IR)3T3-L1 adipocytes.Methods TheIRmodelof3T3-L1adipocyteswasinducedby high glucose and hyperinsulinism cultivation(also con-taining dexamethasone ).The adipocytes were treated with rosiglitazone(Ros)and different concentrations of SHD(2. 5,5,10,20,40 g·L-1 )for 24 h.The content of glucose disappeared from the culture medium was determined as glucose consumption of the cells. The transport of glucose was observed by 2-deoxidation-[3 H]-glucose uptake method.The efflux of nonesteri-fied fatty acids(NEFA)from adipocytes was observed by the concentration of NEFA in the culture medium. The mRNA expression of glucose transporter-4 (GLUT-4)was measured by real-time polymerase chain reac-tion (real-time PCR).The protein expression of GLUT-4wasdetectedbyWesternblot.Results Compared with the Con group,SHD(5,10,20,40 g·L-1 ) could significantly induce the glucose consumption and transportion(P0.05).Conclusion SHDcanin-crease insulin sensitivity by increasing glucose trans-portation and consumption in the 3T3-L1 adipocytes as well as decreasing the NEFA efflux from the cells.

Carnosic Acid Inhibits Lipid Accumulation in 3T3-L1 Adipocytes Through Attenuation of Fatty Acid Desaturation

BACKGROUND: Excess body fat accumulation contributes to the development of metabolic disorders that can cause adverse health effects. Carnosic acid (CA), a major bioactive component of rosemary (Rosemarinus officinalis), has been suggested to possess anti-adipogenic properties. The present study was conducted to elucidate the mechanism underlying the anti-adipogenic effects of CA. METHODS: 3T3-L1 pre-adipocytes were treated with CA (0.1, 1, and 10 muM) from day 0 to day 8 of differentiation. On day 8, biochemical markers of lipid accumulation and the degree of fatty acid desaturation were measured. RESULTS: Oil Red O staining results, triglyceride (TG) accumulation, and glycerol 3-phosphate dehydrogenase activity suggested that CA significantly inhibited lipid accumulation in 3T3-L1 adipocytes. CA significantly decreased mRNA expression of peroxisome proliferator-activated receptor-gamma, sterol regulatory element-binding protein 1, and CCAAT/enhancer binding protein-alpha in a dose-dependent manner. Moreover, it decreased the ratio of both C16:1/C16:0 and C18:1/C18:0, with reduced expression of stearoyl CoA desaturase 1 mRNA and protein. CONCLUSIONS: These results suggest that CA efficiently suppressed adipogenesis in 3T3-L1 adipocytes and its action, at least in part, is associated with the downregulation of adipogenesis-related genes and the fatty acid composition of TG accumulated in adipocytes.

Anti-diabetic effects of Caulerpa lentillifera: Stimulation of insulin secretion in pancreatic ß-cells and enhancement of glucose uptake in adipocytes

Objective: To evaluate anti-diabetic effect of Caulerpa lentillifera (C. lentillifera). Methods: The inhibitory effect of C. lentillifera extract on dipeptidyl peptidase-IV and α-glucosidase enzyme was measured in a cell free system. Then, interleukin-1ß and interferon-γ induced cell death and insulin secretion were measured in rat insulinoma (RIN) cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and ELISA kit, respectively. Glucose uptake and glucose transporter expression were measured by fluorometry and western blotting, using 3T3-L1 adipocytes. Results: C. lentillifera extract significantly decreased dipeptidyl peptidase-IV and α-glucosidase enzyme activities, and effectively inhibited cell death and iNOS expression in interleukin-1ß and interferon-γ induced RIN cells. Furthermore, C. lentillifera extract significantly enhanced insulin secretion in RIN cells and glucose transporter expression and glucose uptake in 3T3-L1 adipocytes. Conclusions: Thus, our results suggest that C. lentillifera could be used as a potential anti-diabetic agent.

Effects of 3'-hydroxy puerarin on improving insulin resistance in 3T3-L1 adipocytes and their mechanisms / 中草药

Objective: To investigate the effects of 3'-hydroxy puerarin on improving insulin resistance in 3T3-L1 adipocytes and their mechanisms. Methods: The proliferation of 3T3-L1 preadipocytes was tested by MTT assay and the differentiation by oil red O staining. The insulin resistance model was induced by dexamethasone. Cellular glucose consumption was determined by GOD-POD assay and the concentration of FFA by colorimetric methods. The expression of PPARγ and PTP1B genes in insulin resistant adipocytes was analyzed by qPCR. The PPARγ-transactivation activity of 3'-hydroxy puerarin was examined by using a hybrid reporter gene assay and the activity of PTP1B by colorimetric methods. Results: Compared with the medium control group, 3'-hydroxy puerarin significantly activated PPARγ at 0.1 and 10 μmol/L (P 0.05); increased the proliferation and differentiation of 3T3-L1 preadipocytes at 1-10 μmol/L (P 0.05). Conclusion: 3'-Hydroxy puerarin can improve the insulin resistance via up-regulating the expression of PPARγ.

Effects of dihydromyricetin on insulin resistance in 3 T3-L1 adipocytes and its mechanism / 中国药理学通报

Aim To investigate the effect of dihydro-myricetin (DMY) on the insulin resistance in 3T3-L1 adipocytes and its mechanism. Methods The differ-entiated adipocytes were treated with 1 μmol · L-1 dexamethasone ( dex ) for 7 days to induce insulin re-sistance. With or without insulin, DMY (1 × 10 -6 ~ 1 × 10 -8 mol·L-1 ) was exposed to the normal and in-sulin-resistant 3 T3-L1 adipocytes for 48 hour and 72 hour, respectively. Rosiglitazone ( 1 × 10 -6 mol · L-1 ) was used as a positive control. The glucose up-take was evaluated by glucose consumption. The mR-NA expressions of glucose transporter 4 ( GLUT4 ) , protein kinase B ( PKB/Akt) and adiponectin were de-termined by RT-PCR analysis. Results DMY ( 5 × 10 -7 ~ 1 × 10 -8 mol·L-1 ) concentration-dependently increased the glucose uptake in insulin-resistant 3 T3-L1 adipocytes, similar to rosiglitazone. However, DMY did not affect the glucose consumption in normal 3T3-L1 cells. After treatment of DMY to insulin-resist-ant 3T3-L1 adipocytes for 72 hours, the expressions of GLUT4 , Akt2 and adiponectin mRNA were markedly increased, compared with the dexamethasone-treated group. Conclusion DMY could improve the insulin resistance in 3T3-L1 adipocytes, which is related to in-creasing the mRNA expression of GLUT4 , Akt2 and adiponectin.

Anti-diabetic effects of Caulerpa lentillifera：stimulation of insulin secretion in pancreatic β-cells and enhancement of glucose uptake in adipocytes

Objective: To evaluate anti-diabetic effect of Caulerpa lentillifera (C. lentillifera).Methods:The inhibitory effect of C. lentillifera extract on dipeptidyl peptidase-IV andα-glucosidase enzyme was measured in a cell free system. Then, interleukin-1β and interferon-γinduced cell death and insulin secretion were measured in rat insulinoma (RIN) cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and ELISA kit, respectively. Glucose uptake and glucose transporter expression were measured by fluorometry and western blotting, using 3T3-L1 adipocytes.Results: C. lentillifera extract significantly decreased dipeptidyl peptidase-IV and α-glucosidase enzyme activities, and effectively inhibited cell death and iNOS expression in interleukin-1βand interferon-γ induced RIN cells. Furthermore, C. lentillifera extract significantly enhanced insulin secretion in RIN cells and glucose transporter expression and glucose uptake in 3T3-L1 adipocytes.Conclusions:Thus, our results suggest that C. lentillifera could be used as a potential anti-diabetic agent.

Carnosic acid inhibits TLR4-MyD88 signaling pathway in LPS-stimulated 3T3-L1 adipocytes

BACKGROUND/OBJECTIVES: Carnosic acid (CA), found in rosemary (Rosemarinus officinalis) leaves, is known to exhibit anti-obesity and anti-inflammatory activities. However, whether its anti-inflammatory potency can contribute to the amelioration of obesity has not been elucidated. The aim of the current study was to investigate the effect of CA on Toll-like receptor 4 (TLR4) pathways in the presence of lipopolysaccharide (LPS) in 3T3-L1 adipocytes. MATERIALS/METHODS: 3T3-L1 adipocytes were treated with CA (0-20 microM) for 1 h, followed by treatment with LPS for 30 min; mRNA expression of adipokines and protein expression of TLR4-related molecules were then measured. RESULTS: LPS-stimulated 3T3-L1 adipocytes showed elevated mRNA expression of tumor necrosis factor (TNF)-alpha, interleukin-6, and monocyte chemoattractant protein-1, and CA significantly inhibited the expression of these adipokine genes. LPS-induced up regulation of TLR4, myeloid differentiation factor 88, TNF receptor-associated factor 6, and nuclear factor-kappaB, as well as phosphorylated extracellular receptor-activated kinase were also suppressed by pre-treatment of 3T3-L1 adipocytes with CA. CONCLUSIONS: Results of this study suggest that CA directly inhibits TLR4-MyD88-dependent signaling pathways and decreases the inflammatory response in adipocytes.